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Choi J, Jang H, Xuan Z, Park D. Emerging roles of ATG9/ATG9A in autophagy: implications for cell and neurobiology. Autophagy 2024:1-15. [PMID: 39099167 DOI: 10.1080/15548627.2024.2384349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2024] [Revised: 07/01/2024] [Accepted: 07/22/2024] [Indexed: 08/06/2024] Open
Abstract
Atg9, the only transmembrane protein among many autophagy-related proteins, was first identified in the year 2000 in yeast. Two homologs of Atg9, ATG9A and ATG9B, have been found in mammals. While ATG9B shows a tissue-specific expression pattern, such as in the placenta and pituitary gland, ATG9A is ubiquitously expressed. Additionally, ATG9A deficiency leads to severe defects not only at the molecular and cellular levels but also at the organismal level, suggesting key and fundamental roles for ATG9A. The subcellular localization of ATG9A on small vesicles and its functional relevance to autophagy have suggested a potential role for ATG9A in the lipid supply during autophagosome biogenesis. Nevertheless, the precise role of ATG9A in the autophagic process has remained a long-standing mystery, especially in neurons. Recent findings, however, including structural, proteomic, and biochemical analyses, have provided new insights into its function in the expansion of the phagophore membrane. In this review, we aim to understand various aspects of ATG9 (in invertebrates and plants)/ATG9A (in mammals), including its localization, trafficking, and other functions, in nonneuronal cells and neurons by comparing recent discoveries related to ATG9/ATG9A and proposing directions for future research.Abbreviation: AP-4: adaptor protein complex 4; ATG: autophagy related; cKO: conditional knockout; CLA-1: CLArinet (functional homolog of cytomatrix at the active zone proteins piccolo and fife); cryo-EM: cryogenic electron microscopy; ER: endoplasmic reticulum; KO: knockout; PAS: phagophore assembly site; PtdIns3K: class III phosphatidylinositol 3-kinase; PtdIns3P: phosphatidylinositol-3-phosphate; RB1CC1/FIP200: RB1 inducible coiled-coil 1; SV: synaptic vesicle; TGN: trans-Golgi network; ULK: unc-51 like autophagy activating kinase; WIPI2: WD repeat domain, phosphoinositide interacting 2.
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Affiliation(s)
- Jiyoung Choi
- Department of Medical and Biological Sciences, The Catholic University of Korea, Bucheon, South Korea
- Department of Biotechnology, The Catholic University of Korea, Bucheon, South Korea
| | - Haeun Jang
- Department of Medical and Biological Sciences, The Catholic University of Korea, Bucheon, South Korea
| | - Zhao Xuan
- School of Biology and Ecology, University of Maine, Orono, ME, USA
| | - Daehun Park
- Department of Medical and Biological Sciences, The Catholic University of Korea, Bucheon, South Korea
- Department of Biotechnology, The Catholic University of Korea, Bucheon, South Korea
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Nasr M, Fay A, Lupieri A, Malet N, Darmon A, Zahreddine R, Swiader A, Wahart A, Viaud J, Nègre-Salvayre A, Hirsch E, Monteyne D, Perez-Morgà D, Dupont N, Codogno P, Ramel D, Morel E, Laffargue M, Gayral S. PI3KCIIα-Dependent Autophagy Program Protects From Endothelial Dysfunction and Atherosclerosis in Response to Low Shear Stress in Mice. Arterioscler Thromb Vasc Biol 2024; 44:620-634. [PMID: 38152888 DOI: 10.1161/atvbaha.123.319978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 12/12/2023] [Indexed: 12/29/2023]
Abstract
BACKGROUND The ability to respond to mechanical forces is a basic requirement for maintaining endothelial cell (ECs) homeostasis, which is continuously subjected to low shear stress (LSS) and high shear stress (HSS). In arteries, LSS and HSS have a differential impact on EC autophagy processes. However, it is still unclear whether LSS and HSS differently tune unique autophagic machinery or trigger specific autophagic responses in ECs. METHODS Using fluid flow system to generate forces on EC and multiscale imaging analyses on ApoE-/- mice whole arteries, we studied the cellular and molecular mechanism involved in autophagic response to LSS or HSS on the endothelium. RESULTS We found that LSS and HSS trigger autophagy activation by mobilizing specific autophagic signaling modules. Indeed, LSS-induced autophagy in endothelium was independent of the class III PI3K (phosphoinositide 3-kinase) VPS34 (vacuolar sorting protein 34) but controlled by the α isoform of class II PI3K (phosphoinositide 3-kinase class II α [PI3KCIIα]). Accordingly, reduced PI3KCIIα expression in ApoE-/- mice (ApoE-/-PI3KCIIα+/-) led to EC dysfunctions associated with increased plaque deposition in the LSS regions. Mechanistically, we revealed that PI3KCIIα inhibits mTORC1 (mammalian target of rapamycin complex 1) activation and that rapamycin treatment in ApoE-/-PI3KCIIα+/- mice specifically rescue autophagy in arterial LSS regions. Finally, we demonstrated that absence of PI3KCIIα led to decreased endothelial primary cilium biogenesis in response to LSS and that ablation of primary cilium mimics PI3KCIIα-decreased expression in EC dysfunction, suggesting that this organelle could be the mechanosensor linking PI3KCIIα and EC homeostasis. CONCLUSIONS Our data reveal that mechanical forces variability within the arterial system determines EC autophagic response and supports a central role of PI3KCIIα/mTORC1 axis to prevent EC dysfunction in LSS regions.
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Affiliation(s)
- Mouin Nasr
- Institute of Metabolic and Cardiovascular Diseases (I2MC), Institut national de la Santé et de la Recherche (INSERM) 1297, University of Toulouse 3, France (M.N., A.F., A.L., N.M., A.D., R.Z., A.S., A.W., J.V., A.N.-S., D.R., M.L., S.G.)
| | - Alexis Fay
- Institute of Metabolic and Cardiovascular Diseases (I2MC), Institut national de la Santé et de la Recherche (INSERM) 1297, University of Toulouse 3, France (M.N., A.F., A.L., N.M., A.D., R.Z., A.S., A.W., J.V., A.N.-S., D.R., M.L., S.G.)
| | - Adrien Lupieri
- Institute of Metabolic and Cardiovascular Diseases (I2MC), Institut national de la Santé et de la Recherche (INSERM) 1297, University of Toulouse 3, France (M.N., A.F., A.L., N.M., A.D., R.Z., A.S., A.W., J.V., A.N.-S., D.R., M.L., S.G.)
| | - Nicole Malet
- Institute of Metabolic and Cardiovascular Diseases (I2MC), Institut national de la Santé et de la Recherche (INSERM) 1297, University of Toulouse 3, France (M.N., A.F., A.L., N.M., A.D., R.Z., A.S., A.W., J.V., A.N.-S., D.R., M.L., S.G.)
| | - Anne Darmon
- Institute of Metabolic and Cardiovascular Diseases (I2MC), Institut national de la Santé et de la Recherche (INSERM) 1297, University of Toulouse 3, France (M.N., A.F., A.L., N.M., A.D., R.Z., A.S., A.W., J.V., A.N.-S., D.R., M.L., S.G.)
| | - Rana Zahreddine
- Institute of Metabolic and Cardiovascular Diseases (I2MC), Institut national de la Santé et de la Recherche (INSERM) 1297, University of Toulouse 3, France (M.N., A.F., A.L., N.M., A.D., R.Z., A.S., A.W., J.V., A.N.-S., D.R., M.L., S.G.)
| | - Audrey Swiader
- Institute of Metabolic and Cardiovascular Diseases (I2MC), Institut national de la Santé et de la Recherche (INSERM) 1297, University of Toulouse 3, France (M.N., A.F., A.L., N.M., A.D., R.Z., A.S., A.W., J.V., A.N.-S., D.R., M.L., S.G.)
| | - Amandine Wahart
- Institute of Metabolic and Cardiovascular Diseases (I2MC), Institut national de la Santé et de la Recherche (INSERM) 1297, University of Toulouse 3, France (M.N., A.F., A.L., N.M., A.D., R.Z., A.S., A.W., J.V., A.N.-S., D.R., M.L., S.G.)
| | - Julien Viaud
- Institute of Metabolic and Cardiovascular Diseases (I2MC), Institut national de la Santé et de la Recherche (INSERM) 1297, University of Toulouse 3, France (M.N., A.F., A.L., N.M., A.D., R.Z., A.S., A.W., J.V., A.N.-S., D.R., M.L., S.G.)
| | - Anne Nègre-Salvayre
- Institute of Metabolic and Cardiovascular Diseases (I2MC), Institut national de la Santé et de la Recherche (INSERM) 1297, University of Toulouse 3, France (M.N., A.F., A.L., N.M., A.D., R.Z., A.S., A.W., J.V., A.N.-S., D.R., M.L., S.G.)
| | - Emilio Hirsch
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Torino, Turin, Italy (E.H.)
| | - Daniel Monteyne
- IBMM-DBM, Department of Molecular Parasitology, University of Brussels, Gosselies, Belgium (D.M., D.P.-M.)
| | - David Perez-Morgà
- IBMM-DBM, Department of Molecular Parasitology, University of Brussels, Gosselies, Belgium (D.M., D.P.-M.)
| | - Nicolas Dupont
- Institut Necker-Enfants Malades (INEM), INSERM U1151-CNRS UMR 8253, Université Paris Descartes-Sorbonne Paris Cité, France (N.D., P.C., E.M.)
| | - Patrice Codogno
- Institut Necker-Enfants Malades (INEM), INSERM U1151-CNRS UMR 8253, Université Paris Descartes-Sorbonne Paris Cité, France (N.D., P.C., E.M.)
| | - Damien Ramel
- Institute of Metabolic and Cardiovascular Diseases (I2MC), Institut national de la Santé et de la Recherche (INSERM) 1297, University of Toulouse 3, France (M.N., A.F., A.L., N.M., A.D., R.Z., A.S., A.W., J.V., A.N.-S., D.R., M.L., S.G.)
| | - Etienne Morel
- Institut Necker-Enfants Malades (INEM), INSERM U1151-CNRS UMR 8253, Université Paris Descartes-Sorbonne Paris Cité, France (N.D., P.C., E.M.)
| | - Muriel Laffargue
- Institute of Metabolic and Cardiovascular Diseases (I2MC), Institut national de la Santé et de la Recherche (INSERM) 1297, University of Toulouse 3, France (M.N., A.F., A.L., N.M., A.D., R.Z., A.S., A.W., J.V., A.N.-S., D.R., M.L., S.G.)
| | - Stephanie Gayral
- Institute of Metabolic and Cardiovascular Diseases (I2MC), Institut national de la Santé et de la Recherche (INSERM) 1297, University of Toulouse 3, France (M.N., A.F., A.L., N.M., A.D., R.Z., A.S., A.W., J.V., A.N.-S., D.R., M.L., S.G.)
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Jobst M, Hossain M, Kiss E, Bergen J, Marko D, Del Favero G. Autophagy modulation changes mechano-chemical sensitivity of T24 bladder cancer cells. Biomed Pharmacother 2024; 170:115942. [PMID: 38042111 DOI: 10.1016/j.biopha.2023.115942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 10/27/2023] [Accepted: 11/21/2023] [Indexed: 12/04/2023] Open
Abstract
Bladder cancer cells possess unique adaptive capabilities: shaped by their environment, cells face a complex chemical mixture of metabolites and xenobiotics accompanied by physiological mechanical cues. These responses might translate into resistance to chemotherapeutical regimens and can largely rely on autophagy. Considering molecules capable of rewiring tumor plasticity, compounds of natural origin promise to offer valuable options. Fungal derived metabolites, such as bafilomycin and wortmannin are widely acknowledged as autophagy inhibitors. Here, their potential to tune bladder cancer cells´ adaptability to chemical and physical stimuli was assessed. Additionally, dietary occurring mycotoxins were also investigated, namely deoxynivalenol (DON, 0.1-10 µM) and fusaric acid (FA, 0.1-1 mM). Endowing a Janus' face behavior, DON and FA are on the one side described as toxins with detrimental health effects. Concomitantly, they are also explored experimentally for selective pharmacological applications including anticancer activities. In non-cytotoxic concentrations, bafilomycin (BAFI, 1-10 nM) and wortmannin (WORT, 1 µM) modified cell morphology and reduced cancer cell migration. Application of shear stress and inhibition of mechano-gated PIEZO channels reduced cellular sensitivity to BAFI treatment (1 nM). Similarly, for FA (0.5 mM) PIEZO1 expression and inhibition largely aligned with the modulatory potential on cancer cells motility. Additionally, this study highlighted that the activity profile of compounds with similar cytotoxic potential (e.g. co-incubation DON with BAFI or FA with WORT) can diverge substantially in the regulation of cell mechanotransduction. Considering the interdependence between tumor progression and response to mechanical cues, these data promise to provide a novel viewpoint for the study of chemoresistance and associated pathways.
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Affiliation(s)
- Maximilian Jobst
- Department of Food Chemistry and Toxicology, University of Vienna Faculty of Chemistry, Währinger Str. 38-40, 1090 Vienna, Austria; Core Facility Multimodal Imaging, University of Vienna Faculty of Chemistry, Währinger Str. 38-40, 1090 Vienna, Austria; University of Vienna, Vienna Doctoral School in Chemistry (DoSChem), Währinger Str. 42, 1090 Vienna, Austria
| | - Maliha Hossain
- Department of Food Chemistry and Toxicology, University of Vienna Faculty of Chemistry, Währinger Str. 38-40, 1090 Vienna, Austria
| | - Endre Kiss
- Core Facility Multimodal Imaging, University of Vienna Faculty of Chemistry, Währinger Str. 38-40, 1090 Vienna, Austria
| | - Janice Bergen
- Department of Food Chemistry and Toxicology, University of Vienna Faculty of Chemistry, Währinger Str. 38-40, 1090 Vienna, Austria; Core Facility Multimodal Imaging, University of Vienna Faculty of Chemistry, Währinger Str. 38-40, 1090 Vienna, Austria; University of Vienna, Vienna Doctoral School in Chemistry (DoSChem), Währinger Str. 42, 1090 Vienna, Austria
| | - Doris Marko
- Department of Food Chemistry and Toxicology, University of Vienna Faculty of Chemistry, Währinger Str. 38-40, 1090 Vienna, Austria
| | - Giorgia Del Favero
- Department of Food Chemistry and Toxicology, University of Vienna Faculty of Chemistry, Währinger Str. 38-40, 1090 Vienna, Austria; Core Facility Multimodal Imaging, University of Vienna Faculty of Chemistry, Währinger Str. 38-40, 1090 Vienna, Austria.
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Pikul J, Rzepakowska A, Machnicki M, Stokłosa T. FGFR2 point mutation in 2 cases of pleomorphic adenoma progressing to myoepithelial carcinoma. Contemp Oncol (Pozn) 2023; 27:211-216. [PMID: 38239864 PMCID: PMC10793617 DOI: 10.5114/wo.2023.133592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 11/13/2023] [Indexed: 01/22/2024] Open
Abstract
Introduction Salivary gland tumours are rare neoplasms. Pleomorphic adenoma (PA) is the most frequent benign lesion. Myoepithelial carcinoma (MECA) is rarely recognized malignancy, but the prognosis is unfavourable. The aim of this study was to identify genetic rearrangements that might be responsible for dynamic MECA progression in patients with primary radical PA excision. Material and methods Next-generation sequencing (NGS) of 1500 gene coding sequences was performed in primary and recurrent tumour tissue collected from 2 patients, in whom PA was initially diagnosed and within one year multifocal MECA was detected. Formalin-fixed paraffin-embedded blocks with tumour tissues were subject to NGS analysis, involving small-scale mutations, as well as focal and chromosomal arm-level copy number changes. Results This study showed mutations in the FGFR2 gene in PA and MECA tissues, obtained from both patients. One of them, pathogenic mutation p.Pro253Arg, was associated with sensitivity to registered drug inhibitors. Additionally, FGFR1, EGFR, and CDK4/CDK6 amplification, as well as CDKN2A/B deletion, were detected in one case. Furthermore, mutations in suppressor gene APC2 and PIK3C2A were detected, but only in MECA tissue. The analysis also identified the following chromosomal copy alterations: 4q12-q13.3, 9p21.3, 5q23.1-q34, del8p23.3-p12, and del13q21.31-q31.1. Conclusions Rearrangement of the FGFR2 gene, identified in primary PA and MECA ex PA samples of both our patients, may be responsible for the malignant transformation and the disease progression. Further studies are encouraged to confirm the relevance of the findings. The therapy option with FGFR2 inhibitors may be considered in advanced or metastatic MECA ex PA with confirmed FGFR2 mutations.
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Affiliation(s)
- Julia Pikul
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Warsaw, Poland
| | - Anna Rzepakowska
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Warsaw, Poland
| | - Marcin Machnicki
- Department of Tumour Biology and Genetics, Medical University of Warsaw, Poland
| | - Tomasz Stokłosa
- Department of Tumour Biology and Genetics, Medical University of Warsaw, Poland
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Wu W, Xia X, Tang L, Luo J, Xiong S, Ma G, Lei H. Phosphoinositide 3-kinase as a therapeutic target in angiogenic disease. Exp Eye Res 2023; 236:109646. [PMID: 37716399 DOI: 10.1016/j.exer.2023.109646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 08/30/2023] [Accepted: 09/05/2023] [Indexed: 09/18/2023]
Abstract
Phosphoinositide 3-kinases (PI3Ks) generate lipids that control multitudinous intracellular cell signaling events which participate in cell survival and proliferation. In addition, PI3K signaling also contributes to metabolism, immunity, angiogenesis and cardiovascular homeostasis, and many diseases. The diverse actions of PI3K stem from the existence of their various isoforms and a variety of protein effectors. Hence, PI3K isoform-specific inhibitors have already achieved a wonderful effect on treating cancer. Herein, we summarize the molecular mechanism of PI3K inhibitors in preventing the permeability of vessels and neovascularization. Additionally, we briefly illustrate how PI3K signaling modulates blood vessel growth and discuss the different roles that PI3K isoforms play in angiogenesis.
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Affiliation(s)
- Wenyi Wu
- Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China; Hunan Key Laboratory of Ophthalmology, Changsha, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China.
| | - Xiaobo Xia
- Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China; Hunan Key Laboratory of Ophthalmology, Changsha, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Luosheng Tang
- Department of Ophthalmology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Jing Luo
- Department of Ophthalmology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Siqi Xiong
- Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China; Hunan Key Laboratory of Ophthalmology, Changsha, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Gaoen Ma
- Department of Ophthalmology, The First Affiliated Hospital of Hainan Medical University, Haikou, 571199, China.
| | - Hetian Lei
- Shenzhen Eye Hospital, Jinan University, Shenzhen Eye Institute, Shenzhen, China.
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Cirillo D, Diceglie M, Nazaré M. Isoform-selective targeting of PI3K: time to consider new opportunities? Trends Pharmacol Sci 2023; 44:601-621. [PMID: 37438206 DOI: 10.1016/j.tips.2023.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Revised: 06/06/2023] [Accepted: 06/07/2023] [Indexed: 07/14/2023]
Abstract
Phosphoinositide-3-kinases (PI3Ks) are central to several cellular signaling pathways in human physiology and are potential pharmacological targets for many pathologies including cancer, thrombosis, and pulmonary diseases. Tremendous efforts to develop isoform-selective inhibitors have culminated in the approval of several drugs, validating PI3K as a tractable and therapeutically relevant target. Although successful therapeutic validation has focused on isoform-selective class I orthosteric inhibitors, recent clinical findings have indicated challenges regarding poor drug tolerance owing to sustained on-target inhibition. Hence, additional approaches are warranted to increase the clinical benefits of specific clinical treatment options, which may involve the employment of so far underexploited targeting modalities or the development of inhibitors for currently underexplored PI3K class II isoforms. We review recent key discoveries in the development of isoform-selective inhibitors, focusing particularly on PI3K class II isoforms, and highlight the emerging importance of developing a broader arsenal of pharmacological tools.
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Affiliation(s)
- Davide Cirillo
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Campus Berlin-Buch, Berlin, Germany
| | - Marta Diceglie
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Campus Berlin-Buch, Berlin, Germany
| | - Marc Nazaré
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Campus Berlin-Buch, Berlin, Germany.
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Chen C, Hu J, Ling K. The Role of Primary Cilia-Associated Phosphoinositide Signaling in Development. J Dev Biol 2022; 10:51. [PMID: 36547473 PMCID: PMC9785882 DOI: 10.3390/jdb10040051] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 11/22/2022] [Accepted: 11/24/2022] [Indexed: 12/07/2022] Open
Abstract
Primary cilia are microtube-based organelles that extend from the cell surface and function as biochemical and mechanical extracellular signal sensors. Primary cilia coordinate a series of signaling pathways during development. Cilia dysfunction leads to a pleiotropic group of developmental disorders, termed ciliopathy. Phosphoinositides (PIs), a group of signaling phospholipids, play a crucial role in development and tissue homeostasis by regulating membrane trafficking, cytoskeleton reorganization, and organelle identity. Accumulating evidence implicates the involvement of PI species in ciliary defects and ciliopathies. The abundance and localization of PIs in the cell are tightly regulated by the opposing actions of kinases and phosphatases, some of which are recently discovered in the context of primary cilia. Here, we review several cilium-associated PI kinases and phosphatases, including their localization along cilia, function in regulating the ciliary biology under normal conditions, as well as the connection of their disease-associated mutations with ciliopathies.
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Affiliation(s)
- Chuan Chen
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN 55905, USA
| | - Jinghua Hu
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN 55905, USA
| | - Kun Ling
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
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C/EBPα-Mediated Transcriptional Activation of PIK3C2A Regulates Autophagy, Matrix Metalloproteinase Expression, and Phenotypic of Vascular Smooth Muscle Cells in Aortic Dissection. J Immunol Res 2022; 2022:7465353. [PMID: 36132983 PMCID: PMC9484969 DOI: 10.1155/2022/7465353] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 08/04/2022] [Accepted: 08/08/2022] [Indexed: 11/24/2022] Open
Abstract
Purpose To investigate the function of C/EBPα in the development of aortic dissection (AD) and the underlying mechanism. Methods Aortic vascular smooth muscle cells (VSMCs) were isolated, cultured, and identified from AD rats. Then, C/EBPα and PIK3C2A were knockdown or overexpressed by siRNA or plasmid transfection, respectively. Rapamycin or 3-MA was utilized to stimulate and restrain autophagy of VSMCs, respectively. Western blot was used to evaluate the expression levels of C/EBPα, PIK3C2A, LC3, Beclin-1, p62, MMP-2, MMP-9, α-SMA, SM-MHC, and OPN. The pathological status of aortic ring was evaluated by stretch stress, and ChIP assay was used to analyze the binding between C/EBPα and PIK3C2A. C/EBPα shRNA was injected into tail vein to observe the effect of C/EBPα knockdown in vivo on phenotype, autophagy of aortic vascular tissue by immunohistochemical staining and Western blot. Results The protein levels of C/EBPα, PIK3C2A, MMP-2, MMP-9, and LC3 in the aorta of AD rats were all upregulated significantly. C/EBPα and rapamycin promoted notable upregulation of the synthesized proteins (OPN), PIK3C2A, matrix metalloproteinases, LC3, and Beclin-1 in VSMCs, while suppressed contractile proteins (α-SMA and SM-MHC) and p62. The opposite results were observed in the C/EBPα-knockdown VSMCs, PIK3C2A-knockdown VSMCs, or VSMCs treated with 3-MA. C/EBPα, PIK3C2A, and LC3 were dramatically upregulated by the stimulation of 3 g and 5 g stretch stress. The downregulated contractile proteins, upregulated synthetic proteins, activated autophagy, and aggravated pathological state in 5 g stretch stress-treated aortic rings were significantly reversed by the knockdown of C/EBPα. ChIP results indicated that there was a binding site for C/EBPα in the promoter of PIK3C2A. C/EBPα also downregulated α-SMA level and upregulated OPN levels in AD rats in vivo. Conclusion Our data indicated that during the development of AD, C/EBPα regulated the transition of VSMC phenotype and extracellular matrix remodeling by activating autophagy through regulating the transcriptional activity of PIK3C2A promoter.
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Galarreta CI, Kennedy C, Blair DR, Slavotinek A. Expanding the phenotype of PIK3C2A related syndrome: Report of two siblings with novel features and genotype. Am J Med Genet A 2022; 188:2724-2731. [PMID: 35770347 DOI: 10.1002/ajmg.a.62881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 04/05/2022] [Accepted: 04/15/2022] [Indexed: 01/25/2023]
Abstract
A pair of siblings was ascertained due to multiple congenital anomalies, including strikingly similar facial, skeletal, and ocular abnormalities. Exome sequencing of both the children and their mother revealed two novel PIK3C2A variants in the siblings, c.4381delC (p.Arg1461Glufs*31) and c.1555C > T (p.Arg519Ter). PIK3C2A belongs to the Class IIa family of Phosphatidylinositol-3-kinases, which create second messenger lipids that regulate a wide range of downstream signaling pathways involved in cell growth, survival and migration. Tiosano et al. (2019) identified the first monogenic disorder associated with biallelic PIK3C2A loss-of-function variants (oculoskeletodental syndrome). The novel syndrome was characterized by short stature, coarse facial features, ocular and skeletal abnormalities. This report describes two additional siblings affected by the PIK3C2A-related syndrome, confirms core clinical features, establishes intrafamilial variability and expands the phenotype to include proteinuria.
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Affiliation(s)
- Carolina I Galarreta
- Medical Genetics and Metabolism Department, Valley Children's Hospital, Madera, California, USA
| | - Colleen Kennedy
- Medical Genetics and Metabolism Department, Valley Children's Hospital, Madera, California, USA
| | - David R Blair
- Department of Pediatrics, Division of Genetics, University of California, San Francisco, California, USA
| | - Anne Slavotinek
- Department of Pediatrics, Division of Genetics, University of California, San Francisco, California, USA
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An Overview of Class II Phosphoinositide 3-Kinases. Curr Top Microbiol Immunol 2022; 436:51-68. [DOI: 10.1007/978-3-031-06566-8_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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11
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Bischoff ME, Zang Y, Chu J, Price AD, Ehmer B, Talbot NJ, Newbold MJ, Paul A, Guan JL, Plas DR, Meller J, Czyzyk-Krzeska MF. Selective MAP1LC3C (LC3C) autophagy requires noncanonical regulators and the C-terminal peptide. J Cell Biol 2021; 220:212107. [PMID: 33988680 PMCID: PMC8129795 DOI: 10.1083/jcb.202004182] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 03/02/2021] [Accepted: 04/19/2021] [Indexed: 12/01/2022] Open
Abstract
LC3s are canonical proteins necessary for the formation of autophagosomes. We have previously established that two paralogs, LC3B and LC3C, have opposite activities in renal cancer, with LC3B playing an oncogenic role and LC3C a tumor-suppressing role. LC3C is an evolutionary late gene present only in higher primates and humans. Its most distinct feature is a C-terminal 20-amino acid peptide cleaved in the process of glycine 126 lipidation. Here, we investigated mechanisms of LC3C-selective autophagy. LC3C autophagy requires noncanonical upstream regulatory complexes that include ULK3, UVRAG, RUBCN, PIK3C2A, and a member of ESCRT, TSG101. We established that postdivision midbody rings (PDMBs) implicated in cancer stem-cell regulation are direct targets of LC3C autophagy. LC3C C-terminal peptide is necessary and sufficient to mediate LC3C-dependent selective degradation of PDMBs. This work establishes a new noncanonical human-specific selective autophagic program relevant to cancer stem cells.
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Affiliation(s)
- Megan E Bischoff
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH
| | - Yuanwei Zang
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH.,Department of Urology, Qilu Hospital, Shandong University, Jinan, People's Republic of China
| | - Johnson Chu
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH
| | - Adam D Price
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH
| | - Birgit Ehmer
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH
| | - Nicholas J Talbot
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH
| | - Michael J Newbold
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH
| | - Anurag Paul
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH
| | - Jun-Lin Guan
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH
| | - David R Plas
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH
| | - Jarek Meller
- Division of Biostatistics and Bioinformatics, Department of Environmental and Public Health Sciences, University of Cincinnati College of Medicine, Cincinnati, OH.,Division of Biomedical Informatics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH.,Department of Biomedical Informatics, University of Cincinnati College of Medicine, Cincinnati, OH.,Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH
| | - Maria F Czyzyk-Krzeska
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH.,Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH.,Cincinnati Veterans Affairs Medical Center, Department of Veterans Affairs, Cincinnati, OH
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12
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Melia TJ, Lystad AH, Simonsen A. Autophagosome biogenesis: From membrane growth to closure. J Cell Biol 2021; 219:151729. [PMID: 32357219 PMCID: PMC7265318 DOI: 10.1083/jcb.202002085] [Citation(s) in RCA: 169] [Impact Index Per Article: 56.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 04/04/2020] [Accepted: 04/06/2020] [Indexed: 12/14/2022] Open
Abstract
Autophagosome biogenesis involves de novo formation of a membrane that elongates to sequester cytoplasmic cargo and closes to form a double-membrane vesicle (an autophagosome). This process has remained enigmatic since its initial discovery >50 yr ago, but our understanding of the mechanisms involved in autophagosome biogenesis has increased substantially during the last 20 yr. Several key questions do remain open, however, including, What determines the site of autophagosome nucleation? What is the origin and lipid composition of the autophagosome membrane? How is cargo sequestration regulated under nonselective and selective types of autophagy? This review provides key insight into the core molecular mechanisms underlying autophagosome biogenesis, with a specific emphasis on membrane modeling events, and highlights recent conceptual advances in the field.
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Affiliation(s)
- Thomas J Melia
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
| | - Alf H Lystad
- Department of Molecular Medicine, Institute of Basic Medical Sciences and Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Anne Simonsen
- Department of Molecular Medicine, Institute of Basic Medical Sciences and Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
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13
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Class II phosphatidylinositol 3-kinase isoforms in vesicular trafficking. Biochem Soc Trans 2021; 49:893-901. [PMID: 33666217 PMCID: PMC8106491 DOI: 10.1042/bst20200835] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 02/12/2021] [Accepted: 02/16/2021] [Indexed: 01/14/2023]
Abstract
Phosphatidylinositol 3-kinases (PI3Ks) are critical regulators of many cellular processes including cell survival, proliferation, migration, cytoskeletal reorganization, and intracellular vesicular trafficking. They are a family of lipid kinases that phosphorylate membrane phosphoinositide lipids at the 3′ position of their inositol rings, and in mammals they are divided into three classes. The role of the class III PI3K Vps34 is well-established, but recent evidence suggests the physiological significance of class II PI3K isoforms in vesicular trafficking. This review focuses on the recently discovered functions of the distinct PI3K-C2α and PI3K-C2β class II PI3K isoforms in clathrin-mediated endocytosis and consequent endosomal signaling, and discusses recently reported data on class II PI3K isoforms in different physiological contexts in comparison with class I and III isoforms.
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14
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Baba T, Balla T. Emerging roles of phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate as regulators of multiple steps in autophagy. J Biochem 2021; 168:329-336. [PMID: 32745205 DOI: 10.1093/jb/mvaa089] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 07/17/2020] [Indexed: 12/13/2022] Open
Abstract
Inositol phospholipids are low-abundance regulatory lipids that orchestrate diverse cellular functions in eukaryotic organisms. Recent studies have uncovered involvement of the lipids in multiple steps in autophagy. The late endosome-lysosome compartment plays critical roles in cellular nutrient sensing and in the control of both the initiation of autophagy and the late stage of eventual degradation of cytosolic materials destined for elimination. It is particularly notable that inositol lipids are involved in almost all steps of the autophagic process. In this review, we summarize how inositol lipids regulate and contribute to autophagy through the endomembrane compartments, primarily focusing on PI4P and PI(4,5)P2.
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Affiliation(s)
- Takashi Baba
- Department of Biological Informatics and Experimental Therapeutics, Graduate School of Medicine, Akita University, 1-1-1 Hondo, Akita, 010-8543, Japan.,Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institutes of Child Health and Human Development, National Institutes of Health, 35A Convent Drive, Bethesda, MD 20892-3752, USA
| | - Tamas Balla
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institutes of Child Health and Human Development, National Institutes of Health, 35A Convent Drive, Bethesda, MD 20892-3752, USA
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15
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Polyphosphate is an extracellular signal that can facilitate bacterial survival in eukaryotic cells. Proc Natl Acad Sci U S A 2020; 117:31923-31934. [PMID: 33268492 DOI: 10.1073/pnas.2012009117] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Polyphosphate is a linear chain of phosphate residues and is present in organisms ranging from bacteria to humans. Pathogens such as Mycobacterium tuberculosis accumulate polyphosphate, and reduced expression of the polyphosphate kinase that synthesizes polyphosphate decreases their survival. How polyphosphate potentiates pathogenicity is poorly understood. Escherichia coli K-12 do not accumulate detectable levels of extracellular polyphosphate and have poor survival after phagocytosis by Dictyostelium discoideum or human macrophages. In contrast, Mycobacterium smegmatis and Mycobacterium tuberculosis accumulate detectable levels of extracellular polyphosphate, and have relatively better survival after phagocytosis by D. discoideum or macrophages. Adding extracellular polyphosphate increased E. coli survival after phagocytosis by D. discoideum and macrophages. Reducing expression of polyphosphate kinase 1 in M. smegmatis reduced extracellular polyphosphate and reduced survival in D. discoideum and macrophages, and this was reversed by the addition of extracellular polyphosphate. Conversely, treatment of D. discoideum and macrophages with recombinant yeast exopolyphosphatase reduced the survival of phagocytosed M. smegmatis or M. tuberculosis D. discoideum cells lacking the putative polyphosphate receptor GrlD had reduced sensitivity to polyphosphate and, compared to wild-type cells, showed increased killing of phagocytosed E. coli and M. smegmatis Polyphosphate inhibited phagosome acidification and lysosome activity in D. discoideum and macrophages and reduced early endosomal markers in macrophages. Together, these results suggest that bacterial polyphosphate potentiates pathogenicity by acting as an extracellular signal that inhibits phagosome maturation.
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BCL2L10/BECN1 modulates hepatoma cells autophagy by regulating PI3K/AKT signaling pathway. Aging (Albany NY) 2020; 11:350-370. [PMID: 30696802 PMCID: PMC6366968 DOI: 10.18632/aging.101737] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 12/18/2018] [Indexed: 01/23/2023]
Abstract
The aim of this study was to investigate BCL2L10 and BECN1 expression and their effect on autophagy in hepatocellular carcinoma (HCC). We found that BCL2L10 expression was low in hepatoma tissues and cells. Overexpression of BCL2L10 decreased the activity of hepatoma cells. To analyze autophagic flux, we monitored the formation of autophagic vesicles by fluorescence protein method. Autophagy-related protein LC3B-II was accumulated and P62 was decreased, which indicated that autophagy was induced by BECN1, while BCL2L10 could suppress this trend. Immunofluorescence assay showed that BCL2L10 and Beclin 1 were co-located in hepatoma cells. Immunoprecipitation showed that BCL2L10 could inhibit the autophagy of hepatoma cells by combining with Beclin 1. ELISA and co-immunoprecipitation suggested that the combination between BCL2L10 and Beclin 1 reduced the bond between Beclin 1 and PI3KC3. Based on Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, the PI3K/AKT signaling pathway was significantly upregulated in HCC. In conclusions, BCL2L10 had a low expression in HCC tissues and cells, which could release BECN1 to induce autophagy of hepatoma cells by downregulating PI3K/AKT signaling pathway.
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O’Hanlon R, Leyva-Grado VH, Sourisseau M, Evans MJ, Shaw ML. An Influenza Virus Entry Inhibitor Targets Class II PI3 Kinase and Synergizes with Oseltamivir. ACS Infect Dis 2019; 5:1779-1793. [PMID: 31448902 DOI: 10.1021/acsinfecdis.9b00230] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Two classes of antivirals targeting the viral neuraminidase (NA) and endonuclease are currently the only clinically useful drugs for the treatment of influenza. However, resistance to both antivirals has been observed in clinical isolates, and there was widespread resistance to oseltamivir (an NA inhibitor) among H1N1 viruses prior to 2009. This potential for resistance and lack of diversity for antiviral targets highlights the need for new influenza antivirals with a higher barrier to resistance. In this study, we identified an antiviral compound, M85, that targets host kinases, epidermal growth factor receptor (EGFR), and phosphoinositide 3 class II β (PIK3C2β) and is not susceptible to resistance by viral mutations. M85 blocks endocytosis of influenza viruses and inhibits a broad-spectrum of viruses with minimal cytotoxicity. In vitro, we found that combinations of M85 and oseltamivir have strong synergism. In the mouse model for influenza, treatment with the combination therapy was more protective against a lethal viral challenge than oseltamivir alone, indicating that development of M85 could lead to combination therapies for influenza. Finally, through this discovery of M85 and its antiviral mechanism, we present the first description of PIK3C2β as a necessary host factor for influenza virus entry.
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18
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Bellio M, Caux M, Vauclard A, Chicanne G, Gratacap MP, Terrisse AD, Severin S, Payrastre B. Phosphatidylinositol 3 monophosphate metabolizing enzymes in blood platelet production and in thrombosis. Adv Biol Regul 2019; 75:100664. [PMID: 31604685 DOI: 10.1016/j.jbior.2019.100664] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 09/19/2019] [Accepted: 09/30/2019] [Indexed: 02/09/2023]
Abstract
Blood platelets, produced by the fragmentation of megakaryocytes, play a key role in hemostasis and thrombosis. Being implicated in atherothrombosis and other thromboembolic disorders, they represent a major therapeutic target for antithrombotic drug development. Several recent studies have highlighted an important role for the lipid phosphatidylinositol 3 monophosphate (PtdIns3P) in megakaryocytes and platelets. PtdIns3P, present in small amounts in mammalian cells, is involved in the control of endocytic trafficking and autophagy. Its metabolism is finely regulated by specific kinases and phosphatases. Class II (α, β and γ) and III (Vps34) phosphoinositide-3-kinases (PI3Ks), INPP4 and Fig4 are involved in the production of PtdIns3P whereas PIKFyve, myotubularins (MTMs) and type II PIPK metabolize PtdIns3P. By regulating the turnover of different pools of PtdIns3P, class II (PI3KC2α) and class III (Vps34) PI3Ks have been recently involved in the regulation of platelet production and functions. These pools of PtdIns3P appear to modulate membrane organization and intracellular trafficking. Moreover, PIKFyve and INPP4 have been recently implicated in arterial thrombosis. In this review, we will discuss the role of PtdIns3P metabolizing enzymes in platelet production and function. Potential new anti-thrombotic therapeutic perspectives based on inhibitors targeting specifically PtdIns3P metabolizing enzymes will also be commented.
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Affiliation(s)
- Marie Bellio
- Inserm U1048 and Université Paul Sabatier, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
| | - Manuella Caux
- Inserm U1048 and Université Paul Sabatier, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
| | - Alicia Vauclard
- Inserm U1048 and Université Paul Sabatier, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
| | - Gaëtan Chicanne
- Inserm U1048 and Université Paul Sabatier, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
| | - Marie-Pierre Gratacap
- Inserm U1048 and Université Paul Sabatier, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
| | - Anne-Dominique Terrisse
- Inserm U1048 and Université Paul Sabatier, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
| | - Sonia Severin
- Inserm U1048 and Université Paul Sabatier, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
| | - Bernard Payrastre
- Inserm U1048 and Université Paul Sabatier, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France; Laboratoire d'Hématologie, Hopital Universitaire de Toulouse, Toulouse, France.
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19
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Gulluni F, De Santis MC, Margaria JP, Martini M, Hirsch E. Class II PI3K Functions in Cell Biology and Disease. Trends Cell Biol 2019; 29:339-359. [DOI: 10.1016/j.tcb.2019.01.001] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 12/21/2018] [Accepted: 01/02/2019] [Indexed: 12/12/2022]
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20
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Guillaume JD, Celano SL, Martin KR, MacKeigan JP. Determining the Impact of Metabolic Nutrients on Autophagy. Methods Mol Biol 2019; 1862:151-162. [PMID: 30315466 DOI: 10.1007/978-1-4939-8769-6_11] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Tumorigenesis relies on the ability of cancer cells to obtain necessary nutrients and fulfill increased energy demands associated with rapid proliferation. However, as a result of increased metabolite consumption and poor vascularization, most cancer cells must survive in a nutrient poor and high cellular stress microenvironment. Cancer cells undergo metabolic reprogramming to evade cell death and ensure proliferation; in particular, cancer cells utilize the catabolic process of autophagy. Autophagy creates an intracellular pool of metabolites by sequestering cytosolic macromolecules in double-membrane vesicles targeted for lysosomal degradation. During times of environmental stress and nutrient starvation, autophagy is upregulated through the dynamic interactions between two nutrient sensing proteins, AMP activated protein kinase (AMPK) and mechanistic target of rapamycin (mTOR), in cooperation with Unc-51 like autophagy activating kinase 1 (ULK1). In this way, a lack of metabolic nutrients plays a critical role in inducing autophagy, while the products of autophagy also serve as readily available fuel for the cell. In this chapter, we describe methods to visualize and quantify autophagy using a fluorescent sensor of autophagic membranes. Thus, the impact of specific nutrients on autophagy can be measured using live-cell fluorescent microscopy.
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Affiliation(s)
| | - Stephanie L Celano
- College of Human Medicine, Michigan State University, Grand Rapids, MI, USA
| | - Katie R Martin
- College of Human Medicine, Michigan State University, Grand Rapids, MI, USA
| | - Jeffrey P MacKeigan
- College of Human Medicine, Michigan State University, Grand Rapids, MI, USA.
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21
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Molecular Basis for Membrane Recruitment by the PX and C2 Domains of Class II Phosphoinositide 3-Kinase-C2α. Structure 2018; 26:1612-1625.e4. [DOI: 10.1016/j.str.2018.08.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 06/05/2018] [Accepted: 08/23/2018] [Indexed: 11/17/2022]
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22
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Lopes F, Keita ÅV, Saxena A, Reyes JL, Mancini NL, Al Rajabi A, Wang A, Baggio CH, Dicay M, van Dalen R, Ahn Y, Carneiro MBH, Peters NC, Rho JM, MacNaughton WK, Girardin SE, Jijon H, Philpott DJ, Söderholm JD, McKay DM. ER-stress mobilization of death-associated protein kinase-1-dependent xenophagy counteracts mitochondria stress-induced epithelial barrier dysfunction. J Biol Chem 2018; 293:3073-3087. [PMID: 29317503 DOI: 10.1074/jbc.ra117.000809] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 12/21/2017] [Indexed: 12/14/2022] Open
Abstract
The gut microbiome contributes to inflammatory bowel disease (IBD), in which bacteria can be present within the epithelium. Epithelial barrier function is decreased in IBD, and dysfunctional epithelial mitochondria and endoplasmic reticulum (ER) stress have been individually associated with IBD. We therefore hypothesized that the combination of ER and mitochondrial stresses significantly disrupt epithelial barrier function. Here, we treated human colonic biopsies, epithelial colonoids, and epithelial cells with an uncoupler of oxidative phosphorylation, dinitrophenol (DNP), with or without the ER stressor tunicamycin and assessed epithelial barrier function by monitoring internalization and translocation of commensal bacteria. We also examined barrier function and colitis in mice exposed to dextran sodium sulfate (DSS) or DNP and co-treated with DAPK6, an inhibitor of death-associated protein kinase 1 (DAPK1). Contrary to our hypothesis, induction of ER stress (i.e. the unfolded protein response) protected against decreased barrier function caused by the disruption of mitochondrial function. ER stress did not prevent DNP-driven uptake of bacteria; rather, specific mobilization of the ATF6 arm of ER stress and recruitment of DAPK1 resulted in enhanced autophagic killing (xenophagy) of bacteria. Of note, epithelia with a Crohn's disease-susceptibility mutation in the autophagy gene ATG16L1 exhibited less xenophagy. Systemic delivery of the DAPK1 inhibitor DAPK6 increased bacterial translocation in DSS- or DNP-treated mice. We conclude that promoting ER stress-ATF6-DAPK1 signaling in transporting enterocytes counters the transcellular passage of bacteria evoked by dysfunctional mitochondria, thereby reducing the potential for metabolic stress to reactivate or perpetuate inflammation.
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Affiliation(s)
- Fernando Lopes
- From the Gastrointestinal Research Group, Departments of Physiology and Pharmacology and
| | - Åsa V Keita
- the Department of Clinical and Experimental Medicine, Division of Surgery, Linköping University, Linköping 581 83, Sweden, and
| | - Alpana Saxena
- From the Gastrointestinal Research Group, Departments of Physiology and Pharmacology and
| | - Jose Luis Reyes
- From the Gastrointestinal Research Group, Departments of Physiology and Pharmacology and
| | - Nicole L Mancini
- From the Gastrointestinal Research Group, Departments of Physiology and Pharmacology and
| | - Ala Al Rajabi
- From the Gastrointestinal Research Group, Departments of Physiology and Pharmacology and
| | - Arthur Wang
- From the Gastrointestinal Research Group, Departments of Physiology and Pharmacology and
| | - Cristiane H Baggio
- From the Gastrointestinal Research Group, Departments of Physiology and Pharmacology and
| | - Michael Dicay
- From the Gastrointestinal Research Group, Departments of Physiology and Pharmacology and
| | - Rob van Dalen
- the Departments of Laboratory Medicine and Pathobiology and
| | - Younghee Ahn
- the Departments of Pediatrics, Clinical Neurosciences, and Physiology and Pharmacology and
| | - Matheus B H Carneiro
- the Department of Microbiology, Immunology and Infectious Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta T2N4N1, Canada
| | - Nathan C Peters
- the Department of Microbiology, Immunology and Infectious Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta T2N4N1, Canada
| | - Jong M Rho
- the Departments of Pediatrics, Clinical Neurosciences, and Physiology and Pharmacology and
| | - Wallace K MacNaughton
- From the Gastrointestinal Research Group, Departments of Physiology and Pharmacology and
| | | | - Humberto Jijon
- Medicine, Calvin, Joan, and Phoebe Snyder Institute for Chronic Diseases, and
| | - Dana J Philpott
- Immunology, University of Toronto, Toronto, Ontario M5S1A1, Canada
| | - Johan D Söderholm
- the Department of Clinical and Experimental Medicine, Division of Surgery, Linköping University, Linköping 581 83, Sweden, and
| | - Derek M McKay
- From the Gastrointestinal Research Group, Departments of Physiology and Pharmacology and
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