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Morana O, Wood W, Gregory CD. The Apoptosis Paradox in Cancer. Int J Mol Sci 2022; 23:ijms23031328. [PMID: 35163253 PMCID: PMC8836235 DOI: 10.3390/ijms23031328] [Citation(s) in RCA: 109] [Impact Index Per Article: 54.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/18/2022] [Accepted: 01/20/2022] [Indexed: 02/01/2023] Open
Abstract
Cancer growth represents a dysregulated imbalance between cell gain and cell loss, where the rate of proliferating mutant tumour cells exceeds the rate of those that die. Apoptosis, the most renowned form of programmed cell death, operates as a key physiological mechanism that limits cell population expansion, either to maintain tissue homeostasis or to remove potentially harmful cells, such as those that have sustained DNA damage. Paradoxically, high-grade cancers are generally associated with high constitutive levels of apoptosis. In cancer, cell-autonomous apoptosis constitutes a common tumour suppressor mechanism, a property which is exploited in cancer therapy. By contrast, limited apoptosis in the tumour-cell population also has the potential to promote cell survival and resistance to therapy by conditioning the tumour microenvironment (TME)-including phagocytes and viable tumour cells-and engendering pro-oncogenic effects. Notably, the constitutive apoptosis-mediated activation of cells of the innate immune system can help orchestrate a pro-oncogenic TME and may also effect evasion of cancer treatment. Here, we present an overview of the implications of cell death programmes in tumour biology, with particular focus on apoptosis as a process with "double-edged" consequences: on the one hand, being tumour suppressive through deletion of malignant or pre-malignant cells, while, on the other, being tumour progressive through stimulation of reparatory and regenerative responses in the TME.
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2
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Dysarz J, Fuellen G, Möller S, Luyten W, Schmitz-Linneweber C, Saul N. Genes implicated in Caenorhabditis elegans and human health regulate stress resistance and physical abilities in aged Caenorhabditis elegans. Biol Lett 2021; 17:20200916. [PMID: 34102068 PMCID: PMC8187008 DOI: 10.1098/rsbl.2020.0916] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 05/17/2021] [Indexed: 12/26/2022] Open
Abstract
Recently, nine Caenorhabditis elegans genes, grouped into two pathways/clusters, were found to be implicated in healthspan in C. elegans and their homologues in humans, based on literature curation, WormBase data mining and bioinformatics analyses. Here, we further validated these genes experimentally in C. elegans. We downregulated the nine genes via RNA interference (RNAi), and their effects on physical function (locomotion in a swim assay) and on physiological function (survival after heat stress) were analysed in aged nematodes. Swim performance was negatively affected by the downregulation of acox-1.1, pept-1, pak-2, gsk-3 and C25G6.3 in worms with advanced age (twelfth day of adulthood) and heat stress resistance was decreased by RNAi targeting of acox-1.1, daf-22, cat-4, pig-1, pak-2, gsk-3 and C25G6.3 in moderately (seventh day of adulthood) or advanced aged nematodes. Only one gene, sad-1, could not be linked to a health-related function in C. elegans with the bioassays we selected. Thus, most of the healthspan genes could be re-confirmed by health measurements in old worms.
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Affiliation(s)
- Jessica Dysarz
- Molecular Genetics Group, Institute of Biology, Humboldt University of Berlin, Berlin 10115, Germany
| | - Georg Fuellen
- Institute for Biostatistics and Informatics in Medicine and Ageing Research, Rostock University Medical Center, Rostock 18057, Germany
| | - Steffen Möller
- Institute for Biostatistics and Informatics in Medicine and Ageing Research, Rostock University Medical Center, Rostock 18057, Germany
| | - Walter Luyten
- Animal Physiology and Neurobiology, Department of Biology, KU Leuven, Leuven 3000, Belgium
| | | | - Nadine Saul
- Molecular Genetics Group, Institute of Biology, Humboldt University of Berlin, Berlin 10115, Germany
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3
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Kawano M, Nagata S. Efferocytosis and autoimmune disease. Int Immunol 2019; 30:551-558. [PMID: 30165442 PMCID: PMC6234909 DOI: 10.1093/intimm/dxy055] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Accepted: 08/21/2018] [Indexed: 12/14/2022] Open
Abstract
An enormous number of cells in the body die by apoptosis during development and under homeostasis. Apoptotic cells are swiftly engulfed by macrophages and digested into units. This removal of apoptotic cells is called ‘efferocytosis’. For efferocytosis, macrophages recognize phosphatidylserine (PtdSer) exposed on the cell surface as an ‘eat me’ signal. In healthy cells, PtdSer is exclusively localized to the inner leaflet of the plasma membrane by the action of flippases. When cells undergo apoptosis, caspase cleaves flippases to inactivate them, while it cleaves pro-scramblases to active scramblases, which quickly translocate PtdSer to the cell surface. The PtdSer is then recognized by PtdSer-binding proteins or by PtdSer receptors on macrophages, which subsequently engulf the apoptotic cells. When efferocytosis fails, apoptotic cells can rupture, releasing cellular materials that can evoke an autoimmune response. Thus, a defect in the PtdSer-exposing or PtdSer-recognizing processes triggers autoimmunity, leading to a systemic lupus erythematosus-type autoimmune disease.
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Affiliation(s)
- Mahiru Kawano
- Laboratory of Biochemistry & Immunology, World Premier International Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan
| | - Shigekazu Nagata
- Laboratory of Biochemistry & Immunology, World Premier International Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan
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4
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Bae DJ, Seo J, Kim SY, Park SY, Do Yoo J, Pyo JH, Cho W, Cho JY, Kim S, Kim IS. ArhGAP12 plays dual roles in Stabilin-2 mediated efferocytosis: Regulates Rac1 basal activity and spatiotemporally turns off the Rac1 to orchestrate phagosome maturation. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1866:1595-1607. [PMID: 31301364 DOI: 10.1016/j.bbamcr.2019.07.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 07/01/2019] [Accepted: 07/08/2019] [Indexed: 12/13/2022]
Abstract
The rapid and precise clearance of apoptotic cells (efferocytosis) involves a series of phagocytic processes through which apoptotic cells are recognized, engulfed, and degraded within phagocytes. The Rho-family GTPases critically rearrange the cytoskeleton for these phagocytic processes, but we know little about the mechanisms by which regulatory proteins control the spatiotemporal activities of the Rho-family GTPases. Here, we identify ArhGAP12 as a functional GTPase-activating protein (GAP) of Rac1 during Stabilin-2 mediated efferocytosis. ArhGAP12 constitutively forms a complex with the phosphatidylserine receptor, Stabilin-2, via direct interaction with the downstream protein, GULP, but is released from the complex when Stabilin-2 interacts with apoptotic cells. When the phagocytic cup is closed and the apoptotic cell is surrounded by the phagosomal membrane, ArhGAP12 localizes to the phagocytic cup via a specific interaction with phosphatidylinositol-4,5-bisphosphate, which is transiently biosynthesized in the phagocytic cup. Down-regulation of ArhGAP12 results in sustained Rac1 activity, arrangement of F-actin, and delayed phagosome-lysosome fusion. Our results collectively suggest that ArhGAP12 carries dual roles in Stabilin-2 mediated efferocytosis: it binds to GULP/Stabilin-2 and switches off Rac1 basal activity and switches on the Rac1 by releasing itself from the complex. In addition, the spatiotemporal membrane targeting of ArhGAP12 inactivates Rac1 in a time-specific and spatially coordinated manner to orchestrate phagosome maturation. This may shed light on how other RhoGAPs spatiotemporally inactivate Rac or Cdc42 during phagocytosis by various cells, in different circumstances.
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Affiliation(s)
- Dong-Jun Bae
- Department of Biochemistry and Cell Biology, Cell and Matrix Research Institute, School of Medicine, Kyungpook National University, Daegu 700-422, Republic of Korea; ASAN Institute for Life Sciences, ASAN Medical Center, Seoul 138-736, Republic of Korea
| | - Junyoung Seo
- Department of Biochemistry and Cell Biology, Cell and Matrix Research Institute, School of Medicine, Kyungpook National University, Daegu 700-422, Republic of Korea
| | - Sang-Yeob Kim
- Department of Biochemistry and Cell Biology, Cell and Matrix Research Institute, School of Medicine, Kyungpook National University, Daegu 700-422, Republic of Korea; ASAN Institute for Life Sciences, ASAN Medical Center, Seoul 138-736, Republic of Korea; Department of Convergence Medicine, University of Ulsan College of Medicine, Seoul 138-736, Republic of Korea
| | - Seung-Yoon Park
- Department of Biochemistry, School of Medicine, Dongguk University, Gyeongju 780-714, Republic of Korea
| | - Jae Do Yoo
- Department of Biochemistry and Cell Biology, Cell and Matrix Research Institute, School of Medicine, Kyungpook National University, Daegu 700-422, Republic of Korea
| | - Jae-Hoon Pyo
- Department of Biochemistry and Cell Biology, Cell and Matrix Research Institute, School of Medicine, Kyungpook National University, Daegu 700-422, Republic of Korea
| | - Wonhwa Cho
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Je-Yoel Cho
- Department of Biochemistry, College of Veterinary Medicine, Seoul National University, Seoul 151-742, Republic of Korea
| | - Soyoun Kim
- Department of Biochemistry and Cell Biology, Cell and Matrix Research Institute, School of Medicine, Kyungpook National University, Daegu 700-422, Republic of Korea.
| | - In-San Kim
- Biomedical Research Institute, Korea Institute of Science and Technology, Seoul 136-791, Republic of Korea; KU-KIST school, Korea University, Seoul 136-701, Republic of Korea.
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5
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Nishi C, Yanagihashi Y, Segawa K, Nagata S. MERTK tyrosine kinase receptor together with TIM4 phosphatidylserine receptor mediates distinct signal transduction pathways for efferocytosis and cell proliferation. J Biol Chem 2019; 294:7221-7230. [PMID: 30846565 DOI: 10.1074/jbc.ra118.006628] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 02/26/2019] [Indexed: 12/12/2022] Open
Abstract
Apoptotic cells expose phosphatidylserine (PtdSer) on their surface, leading to efferocytosis, i.e. their engulfment by resident macrophages that express the PtdSer receptor T cell immunoglobulin mucin receptor 4 (TIM4) and TAM family receptor tyrosine kinase receptors (MERTK, AXL, and TYRO3). TAM family receptors stimulate cell proliferation, and the many aspects of the growth signaling pathway downstream of TAM family receptors have been elucidated previously. However, the signaling cascade for TAM receptor-mediated efferocytosis has been elusive. Here we observed that efferocytosis by mouse-resident peritoneal macrophages was blocked by inhibitors against the MERTK, mitogen-activated protein kinase/extracellular signal-regulated kinase kinase (MEK), AKT Ser/Thr kinase (AKT), focal adhesion kinase (FAK), or STAT6 pathway. Accordingly, apoptotic cells stimulated the phosphorylation of MERTK, ERK, AKT, FAK, and STAT6, but not of IκB or STAT5. A reconstituted efferocytosis system using MERTK- and TIM4-expressing NIH3T3-derived cells revealed that the juxtamembrane and C-terminal regions of MERTK have redundant roles in efferocytosis. The transformation of murine IL-3-dependent Ba/F3 cells (a pro-B cell line) with MERTK and TIM4 enabled them to proliferate in response to apoptotic cells in a PtdSer-dependent manner. This apoptotic cell-induced MERTK-mediated proliferation required both MERTK's juxtamembrane and C-terminal regions and was blocked by inhibitors of not only ERK, AKT, FAK, and STAT6 but also of NF-κB and STAT5 signaling. These results suggest that apoptotic cells stimulate distinct sets of signal transduction pathways via MERTK to induce either efferocytosis or proliferation.
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Affiliation(s)
- Chihiro Nishi
- From the Laboratory of Biochemistry and Immunology, World Premier International Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan
| | - Yuichi Yanagihashi
- From the Laboratory of Biochemistry and Immunology, World Premier International Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan
| | - Katsumori Segawa
- From the Laboratory of Biochemistry and Immunology, World Premier International Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan
| | - Shigekazu Nagata
- From the Laboratory of Biochemistry and Immunology, World Premier International Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan
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6
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Gordon S, Plüddemann A. Macrophage Clearance of Apoptotic Cells: A Critical Assessment. Front Immunol 2018; 9:127. [PMID: 29441073 PMCID: PMC5797608 DOI: 10.3389/fimmu.2018.00127] [Citation(s) in RCA: 125] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 01/16/2018] [Indexed: 12/22/2022] Open
Abstract
As the body continues to grow and age, it becomes essential to maintain a balance between living and dying cells. Macrophages and dendritic cells play a central role in discriminating among viable, apoptotic, and necrotic cells, as selective and efficient phagocytes, without inducing inappropriate inflammation or immune responses. A great deal has been learnt concerning clearance receptors for modified and non-self-ligands on potential targets, mediating their eventual uptake, disposal, and replacement. In this essay, we assess current understanding of the phagocytic recognition of apoptotic cells within their tissue environment; we conclude that efferocytosis constitutes a more complex process than simply removal of corpses, with regulatory interactions between the target and effector cells, which determine the outcome of this homeostatic process.
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Affiliation(s)
- Siamon Gordon
- College of Medicine, Graduate Institute of Biomedical Sciences, Chang Gung University, Taoyuan City, Taiwan.,Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Annette Plüddemann
- Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, United Kingdom
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7
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Liu J, Li M, Li L, Chen S, Wang X. Ubiquitination of the PI3-kinase VPS-34 promotes VPS-34 stability and phagosome maturation. J Cell Biol 2017; 217:347-360. [PMID: 29092895 PMCID: PMC5748982 DOI: 10.1083/jcb.201705116] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 09/19/2017] [Accepted: 09/26/2017] [Indexed: 12/23/2022] Open
Abstract
The class III phosphatidylinositol 3-kinase VPS-34 promotes phagosome closure and maturation. Liu et al. identify UBC-13 as an E2-conjugating enzyme working with the E3 ligase CHN-1 to catalyze K63-linked poly-ubiquitination on VPS-34, which promotes VPS-34 stability and phagosome maturation. Apoptotic cells generated by programmed cell death are engulfed by phagocytes and enclosed within membrane-bound phagosomes. Maturation of apoptotic cell–containing phagosomes leads to formation of phagolysosomes where cell corpses are degraded. The class III phosphatidylinositol 3-kinase (PI3-kinase) VPS-34 coordinates with PIKI-1, a class II PI3-kinase, to produce PtdIns3P on phagosomes, thus promoting phagosome closure and maturation. Here, we identified UBC-13, an E2 ubiquitin–conjugating enzyme that functions in the same pathway with VPS-34 but in parallel to PIKI-1 to regulate PtdIns3P generation on phagosomes. Loss of ubc-13 affects early steps of phagosome maturation, causing accumulation of cell corpses. We found that UBC-13 functions with UEV-1, a noncatalytic E2 variant, and CHN-1, a U-box–containing E3 ubiquitin ligase, to catalyze K63-linked poly-ubiquitination on VPS-34 both in vitro and in Caenorhabditis elegans. Loss of ubc-13, uev-1, or chn-1 disrupts ubiquitin modification of VPS-34 and causes significantly reduced VPS-34 protein levels. Our data suggest that K63-linked ubiquitin modification serves as a general mechanism to modulate VPS-34 stability in multiple processes.
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Affiliation(s)
- Jinchao Liu
- National Institute of Biological Sciences, Beijing, China.,Chinese Academy of Medical Sciences, Beijing, China.,National Laboratory of Biomacromolecules, Chinese Academy of Sciences Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,Peking Union Medical College, Beijing, China
| | - Meijiao Li
- National Laboratory of Biomacromolecules, Chinese Academy of Sciences Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Lin Li
- National Institute of Biological Sciences, Beijing, China
| | - She Chen
- National Institute of Biological Sciences, Beijing, China
| | - Xiaochen Wang
- National Institute of Biological Sciences, Beijing, China .,Chinese Academy of Medical Sciences, Beijing, China.,National Laboratory of Biomacromolecules, Chinese Academy of Sciences Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China.,Peking Union Medical College, Beijing, China
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8
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Yang C, Wang X. Cell biology in China: Focusing on the lysosome. Traffic 2017; 18:348-357. [DOI: 10.1111/tra.12483] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 03/27/2017] [Accepted: 03/27/2017] [Indexed: 12/24/2022]
Affiliation(s)
- Chonglin Yang
- State Key Laboratory of Conservation and Utilization of Bio-Resources in Yunnan, Center for Life Sciences, and School of Life Sciences; Yunnan University; Kunming China
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology; Chinese Academy of Sciences; Beijing China
| | - Xiaochen Wang
- State Key Laboratory of Biomolecules, Institute of Biophysics; Chinese Academy of Sciences; Beijing China
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9
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Yin J, Huang Y, Guo P, Hu S, Yoshina S, Xuan N, Gan Q, Mitani S, Yang C, Wang X. GOP-1 promotes apoptotic cell degradation by activating the small GTPase Rab2 in C. elegans. J Cell Biol 2017; 216:1775-1794. [PMID: 28424218 PMCID: PMC5461019 DOI: 10.1083/jcb.201610001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Revised: 02/10/2017] [Accepted: 03/03/2017] [Indexed: 12/17/2022] Open
Abstract
Rab2 regulates multiple membrane traffic processes, but how it is recruited to and activated on the target membrane remains unclear. Here, Yin et al. identify a conserved protein, GOP-1, that activates UNC-108/Rab2 to promote phagosome, endosome, and DCV maturation. Apoptotic cells generated by programmed cell death are engulfed by phagocytes and enclosed within plasma membrane–derived phagosomes. Maturation of phagosomes involves a series of membrane-remodeling events that are governed by the sequential actions of Rab GTPases and lead to formation of phagolysosomes, where cell corpses are degraded. Here we identified gop-1 as a novel regulator of apoptotic cell clearance in Caenorhabditis elegans. Loss of gop-1 affects phagosome maturation through the RAB-5–positive stage, causing defects in phagosome acidification and phagolysosome formation, phenotypes identical to and unaffected by loss of unc-108, the C. elegans Rab2. GOP-1 transiently associates with cell corpse–containing phagosomes, and loss of its function abrogates phagosomal association of UNC-108. GOP-1 interacts with GDP-bound and nucleotide-free UNC-108/Rab2, disrupts GDI-UNC-108 complexes, and promotes activation and membrane recruitment of UNC-108/Rab2 in vitro. Loss of gop-1 also abolishes association of UNC-108 with endosomes, causing defects in endosome and dense core vesicle maturation. Thus, GOP-1 is an activator of UNC-108/Rab2 in multiple processes.
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Affiliation(s)
- Jianhua Yin
- National Institute of Biological Sciences, Beijing 102206, China.,Graduate Program in Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.,National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Yaling Huang
- National Institute of Biological Sciences, Beijing 102206, China
| | - Pengfei Guo
- National Institute of Biological Sciences, Beijing 102206, China
| | - Siqi Hu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Sawako Yoshina
- Deparment of Physiology, School of Medicine and Institute for Integrated Medical Sciences, Tokyo Women's Medical University, Tokyo 162-8666, Japan
| | - Nan Xuan
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Qiwen Gan
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Shohei Mitani
- Deparment of Physiology, School of Medicine and Institute for Integrated Medical Sciences, Tokyo Women's Medical University, Tokyo 162-8666, Japan
| | - Chonglin Yang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Xiaochen Wang
- National Institute of Biological Sciences, Beijing 102206, China .,Graduate Program in Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.,National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
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10
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Cheng S, Liu K, Yang C, Wang X. Dissecting Phagocytic Removal of Apoptotic Cells in Caenorhabditis elegans. Methods Mol Biol 2017; 1519:265-284. [PMID: 27815886 DOI: 10.1007/978-1-4939-6581-6_18] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The unique features of programmed cell death during C. elegans development provide an outstanding system to decipher the mechanisms governing phagocytic removal of apoptotic cells. Like in many other organisms, phagocytosis in C. elegans involves several essential events, including exposure of eat-me signals on the cell corpse surface, cell corpse recognition and engulfment by phagocytes, and maturation of phagosomes for cell corpse destruction. Forward or reverse genetic approaches, microscopy-based cell biological methods, and biochemical assays have successfully been employed to identify key factors that control different steps of phagocytosis and to understand their functions in these cellular events. In this chapter, we mainly describe how to apply genetic and cell biological approaches to dissect cell corpse removal by phagocytosis in C. elegans.
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Affiliation(s)
- Shiya Cheng
- National Institute of Biological Sciences, No. 7 Science Park Road, Zhongguancun Life Science Park, Beijing, 102206, China
| | - Kai Liu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing, 100101, China
| | - Chonglin Yang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing, 100101, China.
| | - Xiaochen Wang
- National Institute of Biological Sciences, No. 7 Science Park Road, Zhongguancun Life Science Park, Beijing, 102206, China.
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11
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Cheng S, Wang K, Zou W, Miao R, Huang Y, Wang H, Wang X. PtdIns(4,5)P₂ and PtdIns3P coordinate to regulate phagosomal sealing for apoptotic cell clearance. J Cell Biol 2016; 210:485-502. [PMID: 26240185 PMCID: PMC4523610 DOI: 10.1083/jcb.201501038] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
A coincidence detection mechanism regulates phagosomal sealing and couples it with phosphoinositide conversion from PtdIns(4,5)P2 enrichment on unsealed phagosomes to PtdIns3P enrichment on fully sealed phagosomes. Phagocytosis requires phosphoinositides (PIs) as both signaling molecules and localization cues. How PIs coordinate to control phagosomal sealing and the accompanying switch of organelle identity is unclear. In this study, we followed dynamic changes in PIs during apoptotic cell clearance in Caenorhabditis elegans. We found that phosphatidylinositol-4,5-bisphosphate (PtdIns(4,5)P2) and phosphatidylinositol-3-phosphate (PtdIns3P), which accumulate transiently on unsealed and fully sealed phagosomes, respectively, are both involved in phagosome closure. We identified PtdIns3P phosphatase MTM-1 as an effector of PtdIns(4,5)P2 to promote phagosomal sealing. MTM-1 coordinates with the class II PI3 kinase PIKI-1 to control PtdIns3P levels on unsealed phagosomes. The SNX9 family protein LST-4 is required for sealing, and its association with unsealed phagosomes is regulated by PtdIns(4,5)P2, PIKI-1, and MTM-1. Loss of LST-4 or its retention on phagosomes disrupts sealing and suppresses PtdIns3P accumulation, indicating close coupling of the two events. Our findings support a coincidence detection mechanism by which phagosomal sealing is regulated and coupled with conversion from PtdIns(4,5)P2 enrichment on unsealed phagosomes to PtdIns3P enrichment on fully sealed phagosomes.
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Affiliation(s)
- Shiya Cheng
- Graduate Program, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China National Institute of Biological Sciences, Beijing 102206, China
| | - Kun Wang
- National Institute of Biological Sciences, Beijing 102206, China
| | - Wei Zou
- National Institute of Biological Sciences, Beijing 102206, China
| | - Rui Miao
- National Institute of Biological Sciences, Beijing 102206, China
| | - Yaling Huang
- National Institute of Biological Sciences, Beijing 102206, China
| | - Haibin Wang
- National Institute of Biological Sciences, Beijing 102206, China
| | - Xiaochen Wang
- National Institute of Biological Sciences, Beijing 102206, China
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12
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Hall BA, Piterman N, Hajnal A, Fisher J. Emergent stem cell homeostasis in the C. elegans germline is revealed by hybrid modeling. Biophys J 2016. [PMID: 26200879 PMCID: PMC4621618 DOI: 10.1016/j.bpj.2015.06.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The establishment of homeostasis among cell growth, differentiation, and apoptosis is of key importance for organogenesis. Stem cells respond to temporally and spatially regulated signals by switching from mitotic proliferation to asymmetric cell division and differentiation. Executable computer models of signaling pathways can accurately reproduce a wide range of biological phenomena by reducing detailed chemical kinetics to a discrete, finite form. Moreover, coordinated cell movements and physical cell-cell interactions are required for the formation of three-dimensional structures that are the building blocks of organs. To capture all these aspects, we have developed a hybrid executable/physical model describing stem cell proliferation, differentiation, and homeostasis in the Caenorhabditis elegans germline. Using this hybrid model, we are able to track cell lineages and dynamic cell movements during germ cell differentiation. We further show how apoptosis regulates germ cell homeostasis in the gonad, and propose a role for intercellular pressure in developmental control. Finally, we use the model to demonstrate how an executable model can be developed from the hybrid system, identifying a mechanism that ensures invariance in fate patterns in the presence of instability.
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Affiliation(s)
- Benjamin A Hall
- Medical Research Council Cancer Unit, Hutchison/Medical Research Council Research Centre, University of Cambridge, Cambridge, United Kingdom; Microsoft Research Cambridge, Cambridge, UK.
| | - Nir Piterman
- Department of Computer Science, University of Leicester, Leicester, UK
| | - Alex Hajnal
- Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Jasmin Fisher
- Microsoft Research Cambridge, Cambridge, UK; Department of Biochemistry, University of Cambridge, Cambridge, UK.
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13
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Pinto SM, Almendinger J, Cabello J, Hengartner MO. Loss of Acetylcholine Signaling Reduces Cell Clearance Deficiencies in Caenorhabditis elegans. PLoS One 2016; 11:e0149274. [PMID: 26872385 PMCID: PMC4752328 DOI: 10.1371/journal.pone.0149274] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 01/29/2016] [Indexed: 11/18/2022] Open
Abstract
The ability to eliminate undesired cells by apoptosis is a key mechanism to maintain organismal health and homeostasis. Failure to clear apoptotic cells efficiently can cause autoimmune diseases in mammals. Genetic studies in Caenorhabditis elegans have greatly helped to decipher the regulation of apoptotic cell clearance. In this study, we show that the loss of levamisole-sensitive acetylcholine receptor, but not of a typical neuronal acetylcholine receptor causes a reduction in the number of persistent cell corpses in worms suffering from an engulfment deficiency. This reduction is not caused by impaired or delayed cell death but rather by a partial restoration of the cell clearance capacity. Mutants in acetylcholine turn-over elicit a similar phenotype, implying that acetylcholine signaling is the process responsible for these observations. Surprisingly, tissue specific RNAi suggests that UNC-38, a major component of the levamisole-sensitive receptor, functions in the dying germ cell to influence engulfment efficiency. Animals with loss of acetylcholine receptor exhibit a higher fraction of cell corpses positive for the “eat-me” signal phosphatidylserine. Our results suggest that modulation by ion channels of ion flow across plasma membrane in dying cells can influence the dynamics of phosphatidylserine exposure and thus clearance efficiency.
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Affiliation(s)
- Sérgio M. Pinto
- Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
- Graduate Program in Areas of Basic and Applied Biology, University of Porto, Porto, Portugal
| | - Johann Almendinger
- Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Juan Cabello
- Center for Biomedical Research of La Rioja (CIBIR), Logroño, La Rioja, Spain
| | - Michael O. Hengartner
- Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
- * E-mail:
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Abstract
Cell death is a common and important feature of animal development, and cell death defects underlie many human disease states. The nematode Caenorhabditis elegans has proven fertile ground for uncovering molecular and cellular processes controlling programmed cell death. A core pathway consisting of the conserved proteins EGL-1/BH3-only, CED-9/BCL2, CED-4/APAF1, and CED-3/caspase promotes most cell death in the nematode, and a conserved set of proteins ensures the engulfment and degradation of dying cells. Multiple regulatory pathways control cell death onset in C. elegans, and many reveal similarities with tumor formation pathways in mammals, supporting the idea that cell death plays key roles in malignant progression. Nonetheless, a number of observations suggest that our understanding of developmental cell death in C. elegans is incomplete. The interaction between dying and engulfing cells seems to be more complex than originally appreciated, and it appears that key aspects of cell death initiation are not fully understood. It has also become apparent that the conserved apoptotic pathway is dispensable for the demise of the C. elegans linker cell, leading to the discovery of a previously unexplored gene program promoting cell death. Here, we review studies that formed the foundation of cell death research in C. elegans and describe new observations that expand, and in some cases remodel, this edifice. We raise the possibility that, in some cells, more than one death program may be needed to ensure cell death fidelity.
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Affiliation(s)
| | - Shai Shaham
- Laboratory of Developmental Genetics, The Rockefeller University, New York, USA.
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Yang H, Chen YZ, Zhang Y, Wang X, Zhao X, Godfroy JI, Liang Q, Zhang M, Zhang T, Yuan Q, Ann Royal M, Driscoll M, Xia NS, Yin H, Xue D. A lysine-rich motif in the phosphatidylserine receptor PSR-1 mediates recognition and removal of apoptotic cells. Nat Commun 2015; 6:5717. [PMID: 25564762 PMCID: PMC4306451 DOI: 10.1038/ncomms6717] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 10/31/2014] [Indexed: 02/02/2023] Open
Abstract
The conserved phosphatidylserine receptor (PSR) was first identified as a receptor for phosphatidylserine, an 'eat-me' signal exposed by apoptotic cells. However, several studies suggest that PSR may also act as an arginine demethylase, a lysyl hydroxylase, or an RNA-binding protein through its N-terminal JmjC domain. How PSR might execute drastically different biochemical activities, and whether they are physiologically significant, remain unclear. Here we report that a lysine-rich motif in the extracellular domain of PSR-1, the Caenorhabditis elegans PSR, mediates specific phosphatidylserine binding in vitro and clearance of apoptotic cells in vivo. This motif also mediates phosphatidylserine-induced oligomerization of PSR-1, suggesting a mechanism by which PSR-1 activates phagocytosis. Mutations in the phosphatidylserine-binding motif, but not in its Fe(II) binding site critical for the JmjC activity, abolish PSR-1 phagocytic function. Moreover, PSR-1 enriches and clusters around apoptotic cells during apoptosis. These results establish that PSR-1 is a conserved, phosphatidylserine-recognizing phagocyte receptor.
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Affiliation(s)
- Hengwen Yang
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado 80309, USA
| | - Yu-Zen Chen
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado 80309, USA
| | - Yi Zhang
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Xiaohui Wang
- Department of Chemistry &Biochemistry and BioFrontiers Institute, University of Colorado, Boulder, Colorado 80309, USA
| | - Xiang Zhao
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - James I Godfroy
- Department of Chemistry &Biochemistry and BioFrontiers Institute, University of Colorado, Boulder, Colorado 80309, USA
| | - Qian Liang
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Man Zhang
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Tianying Zhang
- National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen 361102, China
| | - Quan Yuan
- National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen 361102, China
| | - Mary Ann Royal
- Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, USA
| | - Monica Driscoll
- Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, USA
| | - Ning-Shao Xia
- National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen 361102, China
| | - Hang Yin
- 1] Department of Chemistry &Biochemistry and BioFrontiers Institute, University of Colorado, Boulder, Colorado 80309, USA [2] Center of Basic Molecular Science and Department of Chemistry, Tsinghua University, Beijing 100082, China
| | - Ding Xue
- 1] Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado 80309, USA [2] School of Life Sciences, Tsinghua University, Beijing 100084, China
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Small GTPase CDC-42 promotes apoptotic cell corpse clearance in response to PAT-2 and CED-1 in C. elegans. Cell Death Differ 2014; 21:845-53. [PMID: 24632947 PMCID: PMC4013519 DOI: 10.1038/cdd.2014.23] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 11/27/2013] [Accepted: 12/17/2013] [Indexed: 12/26/2022] Open
Abstract
The rapid clearance of dying cells is important for the well-being of multicellular organisms. In C. elegans, cell corpse removal is mainly mediated by three parallel engulfment signaling cascades. These pathways include two small GTPases, MIG-2/RhoG and CED-10/Rac1. Here we present the identification and characterization of CDC-42 as a third GTPase involved in the regulation of cell corpse clearance. Genetic analyses performed by both loss of cdc-42 function and cdc-42 overexpression place cdc-42 in parallel to the ced-2/5/12 signaling module, in parallel to or upstream of the ced-10 module, and downstream of the ced-1/6/7 module. CDC-42 accumulates in engulfing cells at membranes surrounding apoptotic corpses. The formation of such halos depends on the integrins PAT-2/PAT-3, UNC-112 and the GEF protein UIG-1, but not on the canonical ced-1/6/7 or ced-2/5/12 signaling modules. Together, our results suggest that the small GTPase CDC-42 regulates apoptotic cell engulfment possibly upstream of the canonical Rac GTPase CED-10, by polarizing the engulfing cell toward the apoptotic corpse in response to integrin signaling and ced-1/6/7 signaling in C. elegans.
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