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Moreno-Corona NC, de León-Bautista MP, León-Juárez M, Hernández-Flores A, Barragán-Gálvez JC, López-Ortega O. Rab GTPases, Active Members in Antigen-Presenting Cells, and T Lymphocytes. Traffic 2024; 25:e12950. [PMID: 38923715 DOI: 10.1111/tra.12950] [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: 01/07/2024] [Revised: 04/25/2024] [Accepted: 05/27/2024] [Indexed: 06/28/2024]
Abstract
Processes such as cell migration, phagocytosis, endocytosis, and exocytosis refer to the intense exchange of information between the internal and external environment in the cells, known as vesicular trafficking. In eukaryotic cells, these essential cellular crosstalks are controlled by Rab GTPases proteins through diverse adaptor proteins like SNAREs complex, coat proteins, phospholipids, kinases, phosphatases, molecular motors, actin, or tubulin cytoskeleton, among others, all necessary for appropriate mobilization of vesicles and distribution of molecules. Considering these molecular events, Rab GTPases are critical components in specific biological processes of immune cells, and many reports refer primarily to macrophages; therefore, in this review, we address specific functions in immune cells, concretely in the mechanism by which the GTPase contributes in dendritic cells (DCs) and, T/B lymphocytes.
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Affiliation(s)
| | - Mercedes Piedad de León-Bautista
- Escuela de Medicina, Universidad Vasco de Quiroga, Morelia, Mexico
- Human Health, Laboratorio de Enfermedades Infecciosas y Genómica (INEX LAB), Morelia, Mexico
| | - Moises León-Juárez
- Laboratorio de Virología Perinatal y Diseño Molecular de Antígenos y Biomarcadores, Departamento de Inmunobioquimica, Instituto Nacional de Perinatología, Ciudad de México, Mexico
| | | | - Juan Carlos Barragán-Gálvez
- División de Ciencias Naturales y Exactas, Departamento de Farmacia, Universidad de Guanajuato, Guanajuato, Mexico
| | - Orestes López-Ortega
- Université Paris Cité, INSERM UMR-S1151, CNRS UMR-S8253, Institute Necker Enfants Malades, Paris, France
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Zheng N, Liu S, Chen J, Xu Y, Cao W, Lin J, Lu G, Zhang G. SARS-CoV-2 NSP2 as a Potential Delivery Vehicle for Proteins. Mol Pharm 2024; 21:1149-1159. [PMID: 38288708 DOI: 10.1021/acs.molpharmaceut.3c00680] [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] [Indexed: 03/05/2024]
Abstract
The development of biomolecule delivery systems is essential for the treatment of various diseases such as cancer, immunological diseases, and metabolic disorders. For the first time, we found that SARS-CoV-2-encoded nonstructural protein 2 (NSP2) can be secreted from the cells, where it is synthesized. Brefeldin A and H89, inhibitors of ER/Golgi secretion pathways, did not inhibit NSP2 secretion. NSP2 is likely secreted via an unconventional secretory pathway. Moreover, both secreted and purified NSP2 proteins were able to traverse the plasma membrane barrier and enter both immortalized human umbilical vein endothelial cells and tumor cell lines. After entry, the NSP2 protein was localized in only the cytoplasm. Cytochalasin D, a potent inhibitor of actin polymerization, inhibited the entry of NSP2. NSP2 can carry other molecules into cells. Burkholderia lethal factor 1, a monomeric toxin from the intracellular pathogen Burkholderia pseudomallei, has demonstrated antitumor activity by targeting host eukaryotic initiation translation factor 4A. An NSP2-BLF1 fusion protein was translocated across the cellular membranes of Huh7 cells and mediated cell killing. By using different approaches, including protein purification, chemical inhibition, and cell imaging, we confirm that NSP2 is able to deliver heterologous proteins into cells. NSP2 can act as a potential delivery vehicle for proteins.
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Affiliation(s)
- Ningze Zheng
- Institute of Human Virology, Department of Pathogen Biology and Biosecurity, and Key Laboratory of Tropical Disease Control of Ministry of Education, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong 510080, China
| | - Shurui Liu
- Institute of Human Virology, Department of Pathogen Biology and Biosecurity, and Key Laboratory of Tropical Disease Control of Ministry of Education, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong 510080, China
| | - Jianheng Chen
- Institute of Human Virology, Department of Pathogen Biology and Biosecurity, and Key Laboratory of Tropical Disease Control of Ministry of Education, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong 510080, China
| | - Yue Xu
- Institute of Human Virology, Department of Pathogen Biology and Biosecurity, and Key Laboratory of Tropical Disease Control of Ministry of Education, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong 510080, China
| | - Wenyin Cao
- Institute of Human Virology, Department of Pathogen Biology and Biosecurity, and Key Laboratory of Tropical Disease Control of Ministry of Education, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong 510080, China
| | - Jinyi Lin
- Department of Physiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong 510080, China
| | - Guang Lu
- Department of Physiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong 510080, China
| | - Guigen Zhang
- Institute of Human Virology, Department of Pathogen Biology and Biosecurity, and Key Laboratory of Tropical Disease Control of Ministry of Education, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong 510080, China
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3
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Cui X, Yao A, Jia L. Starvation insult induces the translocation of high mobility group box 1 to cytosolic compartments in glioma. Oncol Rep 2023; 50:216. [PMID: 37888772 PMCID: PMC10636726 DOI: 10.3892/or.2023.8653] [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: 05/03/2023] [Accepted: 10/04/2023] [Indexed: 10/28/2023] Open
Abstract
High mobility group box 1 (HMGB1) is a highly conserved and ubiquitous nuclear protein in eukaryotic cells. In response to stress, it transfers from the nucleus to the cytoplasm and finally, to the extracellular matrix, participating in inflammation and carcinogenesis. Increased HMGB1 protein levels are frequently associated with the reduced survival of patients with glioma. HMGB1 plays contextual roles depending on its subcellular localization. However, the mechanisms underlying its subcellular localization and secretion remain unclear. In the present study, the subcellular localization and secretion of HMGB1 in starved glioma cells were investigated using immunofluorescence microscopy, enzyme‑linked immunosorbent assay, subcellular fractionation, western blotting and immunoelectron microscopy. The results demonstrated that starvation induced HMGB1 translocation from the nucleus to the cytoplasm and finally, to the extracellular milieu in glioma cells. HMGB1 was localized in the mitochondria, endoplasmic reticulum (ER), peroxisomes, autophagosomes, lysosomes, endosomes and the cytoskeleton. Immunoelectron microscopy confirmed that HMGB1 was present within or around cytosolic compartments. Subcellular fractionation further demonstrated that HMGB1 transferred to membrane‑bound compartments. In addition, HMGB1 was localized to specific contact areas between the ER and mitochondria, known as mitochondria‑associated membranes. On the whole, the results of the present study suggest that starvation induces HMGB1 secretion, which can be inhibited through the suppression of autophagy. Starvation insult induces HMGB1 translocation to the cytosolic compartments of glioma cells, and autophagy may be involved in the extracellular secretion of HMGB1 in starved glioma cells.
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Affiliation(s)
- Xiaohang Cui
- Department of Medical Genetics and Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, Henan 450001, P.R. China
| | - Anhui Yao
- Department of Neurosurgery, 988th Hospital of Joint Logistic Support Force of PLA, Zhengzhou, Henan 450053, P.R. China
| | - Liyun Jia
- Department of Medical Genetics and Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, Henan 450001, P.R. China
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Zhang C, Yang Z, Luo P, Li T, Wang S, Sun F, Gong P, Mei B. Association of TLR4 and TLR9 gene polymorphisms with cervical HR-HPV infection status in Chinese Han population. BMC Infect Dis 2023; 23:152. [PMID: 36915050 PMCID: PMC10012518 DOI: 10.1186/s12879-023-08116-z] [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: 11/03/2022] [Accepted: 02/23/2023] [Indexed: 03/14/2023] Open
Abstract
BACKGROUND Toll-like receptors (TLRs) may be involved in the natural history of human papillomavirus (HPV) infection. In our study, we aimed to investigate the association of TLR4 (rs10116253, rs1927911, rs10759931) and TLR9 (rs187084, rs352140) gene polymorphisms with cervical persistent high-risk HPV (HR-HPV) infection, as well as multiple HR-HPV infections. METHODS A total of 269 study subjects were enrolled and grouped by retrospectively analyzing the HR-HPV testing results and other clinical data of 2647 gynecological outpatients from Jingzhou Hospital Affiliated to Yangtze University. We conducted a case-control study to compare the role of TLR4/TLR9 gene polymorphisms between HR-HPV transient and persistent infections, as well as between HR-HPV single and multiple infections. HR-HPV genotypes were detected using Real-time polymerase chain reaction (RT-PCR). PCR-restriction fragment length polymorphism (PCR-RFLP) was used to determine TLR4 and TLR9 gene polymorphisms. Analyses of the different outcome variables (HR-HPV infection status and time for HR-HPV clearance) with respect to TLR4/TLR9 polymorphisms were carried out. Logistic regression analysis was used to determine the association of TLR4/TLR9 genotypes and alleles with HR-HPV infection status. The Kaplan-Meier method with the log-rank test was used to analyze the relationship between TLR4/TLR9 genotypes and the time for HR-HPV clearance. RESULTS The mutant genotypes of TLR9 rs187084 and rs352140 were associated with persistent (rs187084: CT and CT+CC; rs352140: CT and CT+TT) and multiple (rs187084: CT and CT+CC; rs352140: CT+TT) (all P < 0.05) HR-HPV infection. However, no association was found between TLR4 polymorphisms and HR-HPV infection status. Kaplan-Meier time to HR-HPV clearance analysis demonstrated that women carrying rs187084 and rs352140 mutant genotypes take longer duration to clear HR-HPV infection compared with wild-type genotype carriers (P1 = 0.012; P2 = 0.031). CONCLUSION Our results suggested that TLR9 polymorphisms, but not TLR4, were associated with cervical persistent and multiple HR-HPV infections, which could be useful as a potential predictor of HR-HPV infection status.
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Affiliation(s)
- Chunlin Zhang
- Department of Laboratory Medicine, Jingzhou Hospital Affiliated to Yangtze University, Jingzhou, 434020, Hubei, China
| | - Zhiping Yang
- Department of Laboratory Medicine, Jingzhou Hospital Affiliated to Yangtze University, Jingzhou, 434020, Hubei, China
| | - Ping Luo
- Department of Laboratory Medicine, Jingzhou Hospital Affiliated to Yangtze University, Jingzhou, 434020, Hubei, China
| | - Ting Li
- Department of Laboratory Medicine, Jingzhou Hospital Affiliated to Yangtze University, Jingzhou, 434020, Hubei, China
| | - Sutong Wang
- Department of Laboratory Medicine, Jingzhou Hospital Affiliated to Yangtze University, Jingzhou, 434020, Hubei, China
| | - Fenglan Sun
- Department of Laboratory Medicine, Jingzhou Hospital Affiliated to Yangtze University, Jingzhou, 434020, Hubei, China
| | - Ping Gong
- Department of Pathology, Jingzhou Hospital Affiliated to Yangtze University, Jingzhou, 434020, Hubei, China
| | - Bing Mei
- Department of Laboratory Medicine, Jingzhou Hospital Affiliated to Yangtze University, Jingzhou, 434020, Hubei, China.
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Wu KC, Condon ND, Hill TA, Reid RC, Fairlie DP, Lim J. Ras-Related Protein Rab5a Regulates Complement C5a Receptor Trafficking, Chemotaxis, and Chemokine Secretion in Human Macrophages. J Innate Immun 2023; 15:468-484. [PMID: 36882040 PMCID: PMC10105068 DOI: 10.1159/000530012] [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: 10/12/2022] [Accepted: 03/01/2023] [Indexed: 03/09/2023] Open
Abstract
Complement activation and Rab GTPase trafficking are commonly observed in inflammatory responses. Recruitment of innate immune cells to sites of infection or injury and secretion of inflammatory chemokines are promoted by complement component 5a (C5a) that activates the cell surface protein C5a receptor1 (C5aR1). Persistent activation can lead to a myriad of inflammatory and autoimmune diseases. Here, we demonstrate that the mechanism of C5a induced chemotaxis of human monocyte-derived macrophages (HMDMs) and their secretion of inflammatory chemokines are controlled by Rab5a. We find that C5a activation of the G protein coupled receptor C5aR1 expressed on the surface of HMDMs, recruits β-arrestin2 via Rab5a trafficking, then activates downstream phosphatidylinositol 3-kinase (PI3K)/Akt signaling that culminates in chemotaxis and secretion of pro-inflammatory chemokines from HMDMs. High-resolution lattice light-sheet microscopy on live cells showed that C5a activates C5aR1-GFP internalization and colocalization with Rab5a-tdTomato but not with dominant negative mutant Rab5a-S34N-tdTomato in HEK293 cells. We found that Rab5a is significantly upregulated in differentiated HMDMs and internalization of C5aR1 is dependent on Rab5a. Interestingly, while knockdown of Rab5a inhibited C5aR1-mediated Akt phosphorylation, it did not affect C5aR1-mediated ERK1/2 phosphorylation or intracellular calcium mobilization in HMDMs. Functional analysis using transwell migration and µ-slide chemotaxis assays indicated that Rab5a regulates C5a-induced chemotaxis of HMDMs. Further, C5aR1 was found to mediate interaction of Rab5a with β-arrestin2 but not with G proteins in HMDMs. Furthermore, C5a-induced secretion of pro-inflammatory chemokines (CCL2, CCL3) from HMDMs was attenuated by Rab5a or β-arrestin2 knockdown or by pharmacological inhibition with a C5aR1 antagonist or a PI3K inhibitor. These findings reveal a C5a-C5aR1-β-arrestin2-Rab5a-PI3K signaling pathway that regulates chemotaxis and pro-inflammatory chemokine secretion in HMDMs and suggests new ways of selectively modulating C5a-induced inflammatory outputs.
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Affiliation(s)
- Kai-Chen Wu
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Nicholas D. Condon
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Timothy A. Hill
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Robert C. Reid
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - David P. Fairlie
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Junxian Lim
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
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6
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Maekawa M, Natsume R, Arita M. Functional significance of ion channels during macropinosome resolution in immune cells. Front Physiol 2022; 13:1037758. [DOI: 10.3389/fphys.2022.1037758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 10/10/2022] [Indexed: 11/13/2022] Open
Abstract
Macropinocytosis is a unique type of endocytosis accompanied by membrane ruffle formation. Closure of membrane ruffles leads to the uptake of large volumes of fluid phase and, subsequently, the formation of large vacuoles termed macropinosomes. Immune cells, such as dendritic cells, T cells, and macrophages, endocytose the surrounding amino acids and pathogens via macropinocytosis either constitutively or in a stimulus-dependent fashion. This process is critical for cell migration, mammalian target of rapamycin complex 1 (mTORC1) activation, and antigen presentation. Large vacuoles are fragmented into tubules and smaller vesicles during the progression and maturation of macropinosomes in immune cells. This process is called “macropinosome resolution” and requires osmotically driven shrinkage of macropinosomes, which is controlled by ion channels present in them. The crenation of membranes on shrunken macropinosomes is recognized by curvature-sensing proteins and results in intracellular membrane trafficking. In this mini review, we highlight the recent progress in research on macropinosome resolution in macrophages, with a focus on ion channels (TPC1/2 for Na+ and TMEM206 for Cl−) that is required for macropinosome resolution. We also discuss the potential contribution of membrane lipids to this process.
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Ji H, Hu N. Circular RNA 0001823 aggravates the growth and metastasis of the cervical cancer cells through modulating the microRNA-613/RAB8A axis. Bioengineered 2022; 13:10335-10349. [PMID: 35435110 PMCID: PMC9161891 DOI: 10.1080/21655979.2022.2063665] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
Cervical cancer (CC) is a gynecological cancer, which has become the second malignant tumor with mortality in developing countries. The purpose of current study was to explore the influence of Circular RNA 0001823 (circ_0001823) in the CC development. Thirty CC tissues and paracancerous tissues were obtained, and Hela and CaSki CC cells were purchased for this study. The cell growth was analyzed by CCK-8 and colony formation assays. The cell metastasis was determined with Transwell assay. The circ_0001823, miR-613, and RAB8A expression were analyzed with qRT-PCR analysis. The specific mechanisms of circRNA_0001823 were analyzed by Dual luciferase reporter and RNA pull-down assays. The circ_0001823 and RAB8A expressions were increased, and miR-613 were decreased in the CC cells and tissues. Knockdown of circ_0001823 inhibited the malignant behavior of the CC cells, which was antagonized by miR-613 inhibitor. Over-expressed RAB8A reversed the miR-613 effects in the CC cells. Knockdown of circ_0001823 inhibited the malignant behaviors of the CC cells via regulating the miR-613/RAB8A axis.
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Affiliation(s)
- Hong Ji
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of Jinzhou Medical University, Jinzhou, Liaoning, China
| | - Naijun Hu
- Department of General Surgery, The First Affiliated Hospital of Jinzhou Medical University, Jinzhou, Liaoning, China
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Xu X, Liu X, Dong X, Qiu H, Yang Y, Liu L. Secretory Autophagosomes from Alveolar Macrophages Exacerbate Acute Respiratory Distress Syndrome by Releasing IL-1β. J Inflamm Res 2022; 15:127-140. [PMID: 35027836 PMCID: PMC8752069 DOI: 10.2147/jir.s344857] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 12/24/2021] [Indexed: 12/12/2022] Open
Abstract
Purpose Activated alveolar macrophages (AMs) secrete extracellular vesicles and particles to mediate the inflammatory response in the acute respiratory distress syndrome (ARDS) although the underlying mechanisms are poorly understood. This study investigated whether secretory autophagosomes (SAPs) from AMs contribute to the inflammation-mediated lung injury of ARDS. Methods We first isolated SAPs from cell culture supernatants of RAW264.7 cells and AMs and quantified Interleukin (IL)-1β levels in SAPs. Next, we employed a lipopolysaccharide (LPS)-induced ARDS model to investigate whether SAP-derived IL-1β could exacerbate lung injury. Finally, we used siRNA to knockdown Rab8a, both in vitro and in vivo, to investigate the effect of Rab8a on SAP secretion and lung injury in ARDS. Results We found that AMs play an important role in ARDS by releasing a novel type of proinflammatory vesicles called SAPs that could exacerbate lung injury. SAPs are characterized as double-membrane vesicles (diameter ~200 nm) with the expression of light chain 3 (LC3). IL-1β in SAPs is the key factor that contributes to the inflammation and lung injury in ARDS. We found that Rab8a is necessary for AMs to release SAPs with IL-1β, and Rab8a knockdown alleviated lung injury in ARDS. Conclusion This study showed the novel finding that SAPs released from AMs play a vital role in ARDS by promoting an inflammatory response and the underlying mechanism was associated with IL-1β secretion.
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Affiliation(s)
- Xinyi Xu
- Jiangsu Provincial Key Laboratory of Critical Care Medicine, Department of Critical Care Medicine, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, 210009, People's Republic of China
| | - Xu Liu
- Jiangsu Provincial Key Laboratory of Critical Care Medicine, Department of Critical Care Medicine, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, 210009, People's Republic of China
| | - Xuecheng Dong
- Jiangsu Provincial Key Laboratory of Critical Care Medicine, Department of Critical Care Medicine, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, 210009, People's Republic of China
| | - Haibo Qiu
- Jiangsu Provincial Key Laboratory of Critical Care Medicine, Department of Critical Care Medicine, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, 210009, People's Republic of China
| | - Yi Yang
- Jiangsu Provincial Key Laboratory of Critical Care Medicine, Department of Critical Care Medicine, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, 210009, People's Republic of China
| | - Ling Liu
- Jiangsu Provincial Key Laboratory of Critical Care Medicine, Department of Critical Care Medicine, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, 210009, People's Republic of China
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9
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Abstract
The distinct movements of macropinosome formation and maturation have corresponding biochemical activities which occur in a defined sequence of stages and transitions between those stages. Each stage in the process is regulated by variously phosphorylated derivatives of phosphatidylinositol (PtdIns) which reside in the cytoplasmic face of the membrane lipid bilayer. PtdIns derivatives phosphorylated at the 3' position of the inositol moiety, called 3' phosphoinositides (3'PIs), regulate different stages of the sequence. 3'PIs are synthesized by numerous phosphoinositide 3'-kinases (PI3K) and other lipid kinases and phosphatases, which are themselves regulated by small GTPases of the Ras superfamily. The combined actions of these enzymes localize four principal species of 3'PI to distinct domains of the plasma membrane or to discrete organelles, with distinct biochemical activities confined to those domains. Phosphatidylinositol (3,4,5)-trisphosphate (PtdIns(3,4,5)P3) and phosphatidylinositol (3,4)-bisphosphate (PtdIns(3,4)P2) regulate the early stages of macropinosome formation, which include cell surface ruffling and constrictions of circular ruffles which close into macropinosomes. Phosphatidylinositol 3-phosphate (PtdIns3P) regulates macropinosome fusion with other macropinosomes and early endocytic organelles. Phosphatidylinositol (3,5)-bisphosphate (PtdIns(3,5)P2) mediates macropinosome maturation and shrinkage, through loss of ions and water, and subsequent traffic to lysosomes. The different characteristic rates of macropinocytosis in different cell types indicate levels of regulation which may be governed by the cell's capacity to generate 3'PIs.
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Affiliation(s)
- Joel A Swanson
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, USA.
| | - Nobukazu Araki
- Department of Histology and Cell Biology, School of Medicine, Kagawa University, Miki, Kagawa, Japan
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Lucas RM, Liu L, Curson JEB, Koh YWH, Tuladhar N, Condon ND, Das Gupta K, Burgener SS, Schroder K, Ingley E, Sweet MJ, Stow JL, Luo L. SCIMP is a spatiotemporal transmembrane scaffold for Erk1/2 to direct pro-inflammatory signaling in TLR-activated macrophages. Cell Rep 2021; 36:109662. [PMID: 34496234 DOI: 10.1016/j.celrep.2021.109662] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 07/12/2021] [Accepted: 08/13/2021] [Indexed: 02/06/2023] Open
Abstract
Immune cells are armed with Toll-like receptors (TLRs) for sensing and responding to pathogens and other danger cues. The role of extracellular-signal-regulated kinases 1/2 (Erk1/2) in TLR signaling remains enigmatic, with both pro- and anti-inflammatory functions described. We reveal here that the immune-specific transmembrane adaptor SCIMP is a direct scaffold for Erk1/2 in TLR pathways, with high-resolution, live-cell imaging revealing that SCIMP guides the spatial and temporal recruitment of Erk2 to membrane ruffles and macropinosomes for pro-inflammatory TLR4 signaling. SCIMP-deficient mice display defects in Erk1/2 recruitment to TLR4, c-Fos activation, and pro-inflammatory cytokine production, with these effects being phenocopied by Erk1/2 signaling inhibition. Our findings thus delineate a selective role for SCIMP as a key scaffold for the membrane recruitment of Erk1/2 kinase to initiate TLR-mediated pro-inflammatory responses in macrophages.
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Affiliation(s)
- Richard M Lucas
- Institute for Molecular Bioscience (IMB) and IMB Centre for Inflammation and Disease Research, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Liping Liu
- Institute for Molecular Bioscience (IMB) and IMB Centre for Inflammation and Disease Research, The University of Queensland, Brisbane, QLD 4072, Australia
| | - James E B Curson
- Institute for Molecular Bioscience (IMB) and IMB Centre for Inflammation and Disease Research, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Yvette W H Koh
- Institute for Molecular Bioscience (IMB) and IMB Centre for Inflammation and Disease Research, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Neeraj Tuladhar
- Institute for Molecular Bioscience (IMB) and IMB Centre for Inflammation and Disease Research, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Nicholas D Condon
- Institute for Molecular Bioscience (IMB) and IMB Centre for Inflammation and Disease Research, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Kaustav Das Gupta
- Institute for Molecular Bioscience (IMB) and IMB Centre for Inflammation and Disease Research, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Sabrina S Burgener
- Institute for Molecular Bioscience (IMB) and IMB Centre for Inflammation and Disease Research, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Kate Schroder
- Institute for Molecular Bioscience (IMB) and IMB Centre for Inflammation and Disease Research, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Evan Ingley
- Cell Signalling Group, Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Perth, WA 6009, Australia; Discipline of Medical, Molecular and Forensic Sciences, College of Science, Health, Engineering and Education, Murdoch University, Murdoch, WA 6150, Australia
| | - Matthew J Sweet
- Institute for Molecular Bioscience (IMB) and IMB Centre for Inflammation and Disease Research, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Jennifer L Stow
- Institute for Molecular Bioscience (IMB) and IMB Centre for Inflammation and Disease Research, The University of Queensland, Brisbane, QLD 4072, Australia.
| | - Lin Luo
- Institute for Molecular Bioscience (IMB) and IMB Centre for Inflammation and Disease Research, The University of Queensland, Brisbane, QLD 4072, Australia.
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Sun Z, Huang J, Su L, Li J, Qi F, Su H, Chen Y, Zhang Q, Zhang Q, Li Z, Zhang S. Arf6-mediated macropinocytosis-enhanced suicide gene therapy of C16TAB-condensed Tat/pDNA nanoparticles in ovarian cancer. NANOSCALE 2021; 13:14538-14551. [PMID: 34473182 DOI: 10.1039/d1nr03974a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The use of cell-penetrating peptides (CPPs), typically HIV-Tat, to deliver therapeutic genes for cancer treatment is hampered by the inefficient delivery and complicated uptake route of plasmid DNA (pDNA). On the one hand, surface charges, particle size and shape essentially contribute to the endocytosis pathway of Tat/pDNA nanocomplexes, and on the other hand, endogenous cellular factors dominantly determine their intracellular trafficking fate and biological outcome. Recent advances in surfactant-modified nanomaterial and dual molecular imaging technology have offered new opportunities for suicide gene therapy. In this study, we employed the cationic surfactant C16TAB to further condense Tat/pDNA nanocomplexes for improving their delivery efficiency and tested the therapeutic effect of Tat/pDNA/C16TAB (T-P-C) nanoparticles carrying the GCV-converted HSV-ttk suicide gene for ovarian cancer. The cellular endocytosis pathway and underlying signal mechanism of T-P-C nanoparticles were further determined. The obtained T-P-C nanoparticles exhibited a small size, positive surface charge, irregular granular shape and high pDNA encapsulation efficiency. The in vitro experiments showed that T-P-C nanoparticles mainly used the macropinocytosis pathway for uptake in ovarian cancer cells. Their internalization and payload gene expression were controlled by the Arf6 GTPase-dependent, Rab GTPase-activated signal axis. Further in vivo molecular imaging based on DF (Fluc-eGFP)-TF (RFP-Rluc-HSV-ttk) system showed that T-P-C nanoparticles significantly increased the targeted delivery and suicide gene therapy in a mouse model xenografted with human ovarian cancer. More importantly, Arf6-mediated macropinocytosis remarkably enhanced the delivery efficiency and suicide gene therapy effect of T-P-C nanoparticles. Therefore, these C16TAB-condensed Tat/pDNA nanoparticles combined with the dual molecular imaging strategy provides a novel intracellular delivery platform for high-efficient, precise suicide gene therapy of ovarian cancer.
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Affiliation(s)
- Zhe Sun
- School of Life Sciences, Tianjin University, Weijin Road 92, Tianjin 300072, China
| | - Jinhai Huang
- School of Life Sciences, Tianjin University, Weijin Road 92, Tianjin 300072, China
| | - Linjia Su
- School of Medicine, Nankai University, Tianjin, P.R. China.
| | - Jing Li
- School of Medicine, Nankai University, Tianjin, P.R. China.
| | - Fangzheng Qi
- School of Medicine, Nankai University, Tianjin, P.R. China.
| | - Huishan Su
- School of Medicine, Nankai University, Tianjin, P.R. China.
| | - Yanan Chen
- School of Medicine, Nankai University, Tianjin, P.R. China.
| | - Qing Zhang
- Cancer Hospital of Tianjin Medical University, Tianjin, P.R. China
| | - Qiangzhe Zhang
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, 300350, China
| | - Zongjin Li
- School of Medicine, Nankai University, Tianjin, P.R. China.
| | - Sihe Zhang
- School of Medicine, Nankai University, Tianjin, P.R. China.
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12
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Kawai K, Nishigaki A, Moriya S, Egami Y, Araki N. Rab10-Positive Tubular Structures Represent a Novel Endocytic Pathway That Diverges From Canonical Macropinocytosis in RAW264 Macrophages. Front Immunol 2021; 12:649600. [PMID: 34135890 PMCID: PMC8203412 DOI: 10.3389/fimmu.2021.649600] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 05/11/2021] [Indexed: 12/19/2022] Open
Abstract
Using the optogenetic photo-manipulation of photoactivatable (PA)-Rac1, remarkable cell surface ruffling and the formation of a macropinocytic cup (premacropinosome) could be induced in the region of RAW264 macrophages irradiated with blue light due to the activation of PA-Rac1. However, the completion of macropinosome formation did not occur until Rac1 was deactivated by the removal of the light stimulus. Following PA-Rac1 deactivation, some premacropinosomes closed into intracellular macropinosomes, whereas many others transformed into long Rab10-positive tubules without forming typical macropinosomes. These Rab10-positive tubules moved centripetally towards the perinuclear Golgi region along microtubules. Surprisingly, these Rab10-positive tubules did not contain any endosome/lysosome compartment markers, such as Rab5, Rab7, or LAMP1, suggesting that the Rab10-positive tubules were not part of the degradation pathway for lysosomes. These Rab10-positive tubules were distinct from recycling endosomal compartments, which are labeled with Rab4, Rab11, or SNX1. These findings suggested that these Rab10-positive tubules may be a part of non-degradative endocytic pathway that has never been known. The formation of Rab10-positive tubules from premacropinosomes was also observed in control and phorbol myristate acetate (PMA)-stimulated macrophages, although their frequencies were low. Interestingly, the formation of Rab10-positive premacropinosomes and tubules was not inhibited by phosphoinositide 3-kinase (PI3K) inhibitors, while the classical macropinosome formation requires PI3K activity. Thus, this study provides evidence to support the existence of Rab10-positive tubules as a novel endocytic pathway that diverges from canonical macropinocytosis.
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Affiliation(s)
- Katsuhisa Kawai
- Department of Histology and Cell Biology, School of Medicine, Kagawa University, Miki, Japan
| | - Arata Nishigaki
- Department of Histology and Cell Biology, School of Medicine, Kagawa University, Miki, Japan
| | - Seiji Moriya
- Department of Histology and Cell Biology, School of Medicine, Kagawa University, Miki, Japan
| | - Youhei Egami
- Department of Histology and Cell Biology, School of Medicine, Kagawa University, Miki, Japan
| | - Nobukazu Araki
- Department of Histology and Cell Biology, School of Medicine, Kagawa University, Miki, Japan
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13
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Maxson ME, Sarantis H, Volchuk A, Brumell JH, Grinstein S. Rab5 regulates macropinocytosis by recruiting the inositol 5-phosphatases OCRL and Inpp5b that hydrolyse PtdIns(4,5)P2. J Cell Sci 2021; 134:237783. [PMID: 33722976 DOI: 10.1242/jcs.252411] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 02/25/2021] [Indexed: 01/09/2023] Open
Abstract
Rab5 is required for macropinosome formation, but its site and mode of action remain unknown. We report that Rab5 acts at the plasma membrane, downstream of ruffling, to promote macropinosome sealing and scission. Dominant-negative Rab5, which obliterates macropinocytosis, had no effect on the development of membrane ruffles. However, Rab5-containing vesicles were recruited to circular membrane ruffles, and soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE)-dependent endomembrane fusion was necessary for the completion of macropinocytosis. This fusion event coincided with the disappearance of PtdIns(4,5)P2 that accompanies macropinosome closure. Counteracting the depletion of PtdIns(4,5)P2 by expression of phosphatidylinositol-4-phosphate 5-kinase impaired macropinosome formation. Importantly, we found that the removal of PtdIns(4,5)P2 is dependent on Rab5, through the Rab5-mediated recruitment of the inositol 5-phosphatases OCRL and Inpp5b, via APPL1. Knockdown of OCRL and Inpp5b, or APPL1, prevented macropinosome closure without affecting ruffling. We therefore propose that Rab5 is essential for the clearance of PtdIns(4,5)P2 needed to complete the scission of macropinosomes or to prevent their back-fusion with the plasmalemma.
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Affiliation(s)
- Michelle E Maxson
- Program in Cell Biology, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
| | - Helen Sarantis
- Program in Cell Biology, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
| | - Allen Volchuk
- Program in Cell Biology, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
| | - John H Brumell
- Program in Cell Biology, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada.,SickKids IBD Centre, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada.,Institute of Medical Science, University of Toronto, Toronto, Ontario M5S 1A1, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A1, Canada
| | - Sergio Grinstein
- Program in Cell Biology, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada.,Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada.,Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Ontario M5B 1W8, Canada
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14
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When Rab GTPases meet innate immune signaling pathways. Cytokine Growth Factor Rev 2021; 59:95-100. [PMID: 33608190 DOI: 10.1016/j.cytogfr.2021.01.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 01/15/2021] [Accepted: 01/15/2021] [Indexed: 12/26/2022]
Abstract
Ras-related protein in brain (Rab) GTPases, the subfamily of small GTP-binding proteins superfamily, play a vital role in regulating and controlling vesicles' transport between different membrane-bound organelles. As the first-line defense against invading pathogens, the host's innate immune system recognizes various pathogen-associated molecular patterns through a series of membrane-bound or cytoplasmic pathogen recognition receptors to activate the downstream signaling pathway and induce the type I interferons (IFN-I). Numerous studies have demonstrated that Rab GTPases participate in innate immunity by regulating transmembrane signals' transduction and the transport, adhesion, anchoring, and fusion of vesicles. However, the underlying mechanism of Rab GTPases regulating innate immunity is not entirely understood. A comprehensive understanding of the interplay between the Rab GTPases and innate immunity will help develop novel therapeutics against microbial infections and chronic inflammations.
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15
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Salvany S, Casanovas A, Piedrafita L, Tarabal O, Hernández S, Calderó J, Esquerda JE. Microglial recruitment and mechanisms involved in the disruption of afferent synaptic terminals on spinal cord motor neurons after acute peripheral nerve injury. Glia 2021; 69:1216-1240. [PMID: 33386754 PMCID: PMC7986680 DOI: 10.1002/glia.23959] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 12/11/2020] [Accepted: 12/14/2020] [Indexed: 12/12/2022]
Abstract
Peripheral nerve section with subsequent disconnection of motor neuron (MN) cell bodies from their skeletal muscle targets leads to a rapid reactive response involving the recruitment and activation of microglia. In addition, the loss of afferent synapses on MNs occurs in concomitance with microglial reaction by a process described as synaptic stripping. However, the way in which postaxotomy‐activated microglia adjacent to MNs are involved in synaptic removal is less defined. Here, we used confocal and electron microscopy to examine interactions between recruited microglial cells and presynaptic terminals in axotomized MNs between 1 and 15 days after sciatic nerve transection in mice. We did not observe any bulk engulfment of synaptic boutons by microglia. Instead, microglial cells internalized small membranous‐vesicular fragments which originated from the acute disruption of synaptic terminals involving the activation of the necroptotic pathway. The presence of abundant extracellular vesicles in the perineuronal space after axotomy, together with the increased expression of phospho‐mixed lineage kinase domain‐like protein and, later, of extracellular vesicle markers, such as CD9, CD63, and flotillin, indicate that the vesicles mainly originated in synapses and were transferred to microglia. The upregulation of Rab7 and Rab10 in microglia interacting with injured MNs, indicated the activation of endocytosis. As activated microglia and synaptic boutons displayed positive C1q immunoreactivity, a complement‐mediated opsonization may also contribute to microglial‐mediated synaptic disruption. In addition to the relevance of our data in the context of neuroinflammation and MN disease, they should also be taken into account for understanding functional recovery after peripheral nerve injury.
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Affiliation(s)
- Sara Salvany
- Patologia Neuromuscular Experimental Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Catalonia, Spain
| | - Anna Casanovas
- Patologia Neuromuscular Experimental Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Catalonia, Spain
| | - Lídia Piedrafita
- Patologia Neuromuscular Experimental Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Catalonia, Spain
| | - Olga Tarabal
- Patologia Neuromuscular Experimental Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Catalonia, Spain
| | - Sara Hernández
- Patologia Neuromuscular Experimental Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Catalonia, Spain
| | - Jordi Calderó
- Patologia Neuromuscular Experimental Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Catalonia, Spain
| | - Josep E Esquerda
- Patologia Neuromuscular Experimental Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Catalonia, Spain
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16
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Tong SJ, Lucas RM, Xiao Z, Luo L, Stow JL. Detecting Endogenous Rab8 Activation. Methods Mol Biol 2021; 2293:45-56. [PMID: 34453709 DOI: 10.1007/978-1-0716-1346-7_4] [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] [Indexed: 06/13/2023]
Abstract
The family of Rab GTPases switch between GDP- and GTP-bound forms to interact with effectors and accessory proteins for the regulation of trafficking and signaling pathways in cells. The activation and recruitment of a specific Rab by stimulants or physiological changes can be detected and assessed by measuring the relative amount of the Rab in its active, "GTP-bound" state versus the inactive "GDP-bound" state. While GTP loading can be measured in vitro, current methods to detect the activation state of endogenous Rabs within a cellular context are limited. Here, we developed two molecular probes, based on domains of known Rab effectors, which can be used to pull down endogenous GTP-bound Rab8 from cell extracts as a measure of Rab8 activation. As a test system, we use the lipopolysaccharide (LPS) induced activation of Rab8 in mouse macrophages. The molecular probes compared for capture of GTP-bound Rab8 are derived from two Rab8 effectors, OCRL and PI3Kγ, with the former assessed as being more efficient. We describe how the OCRL-RBD probe is used to assess activation of Rab8 in cell extracts with a method that should be applicable to assessing GTP-bound Rab8 in other cell and tissue extracts.
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Affiliation(s)
- Samuel J Tong
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Richard M Lucas
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Zhijian Xiao
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Lin Luo
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia.
| | - Jennifer L Stow
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia.
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17
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Lin XP, Mintern JD, Gleeson PA. Macropinocytosis in Different Cell Types: Similarities and Differences. MEMBRANES 2020; 10:membranes10080177. [PMID: 32756454 PMCID: PMC7463864 DOI: 10.3390/membranes10080177] [Citation(s) in RCA: 81] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 07/29/2020] [Accepted: 07/30/2020] [Indexed: 12/14/2022]
Abstract
Macropinocytosis is a unique pathway of endocytosis characterised by the nonspecific internalisation of large amounts of extracellular fluid, solutes and membrane in large endocytic vesicles known as macropinosomes. Macropinocytosis is important in a range of physiological processes, including antigen presentation, nutrient sensing, recycling of plasma proteins, migration and signalling. It has become apparent in recent years from the study of specialised cells that there are multiple pathways of macropinocytosis utilised by different cell types, and some of these pathways are triggered by different stimuli. Understanding the physiological function of macropinocytosis requires knowledge of the regulation and fate of the macropinocytosis pathways in a range of cell types. Here, we compare the mechanisms of macropinocytosis in different primary and immortalised cells, identify the gaps in knowledge in the field and discuss the potential approaches to analyse the function of macropinocytosis in vivo.
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18
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Stow JL, Hung Y, Wall AA. Macropinocytosis: Insights from immunology and cancer. Curr Opin Cell Biol 2020; 65:131-140. [PMID: 32745890 DOI: 10.1016/j.ceb.2020.06.005] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 06/25/2020] [Accepted: 06/28/2020] [Indexed: 12/15/2022]
Abstract
Macropinocytosis is increasingly recognized for its versatile adaptations and functions as a highly conserved, ubiquitous pathway for the bulk uptake of fluid, particulate cargo, and membranes. Innate immune cells and transformed cancer cells share the capacity for both constitutive and induced macropinocytosis, which is used for immune surveillance, ingestion of pathogens, immune response shaping, and enhancement of scavenging for nutrients as fuel for cell survival and proliferation. Immunology and cancer biology are leading a resurgence of interest in defining the molecular and physiological regulation of macropinocytosis, partly in pursuit of ways to control macropinocytic uptake in disease settings. New approaches, including high-resolution live imaging, screening of cell surface molecular inventories, biophysics, and exploration of cell microenvironments, have converged to provide new insights into macropinosome induction, formation, and maturation. Recent studies reveal mechanisms for fluid control in and by macrophage macropinosomes that impinge on membrane trafficking and cell migration. EGFR, PTEN, V-ATPase, syndecan 1, and galectin-3 have roles variably in the metabolic regulation of Ras or PI3K signaling for Rac1-mediated macropinocytosis in cancer. These molecular pathways and mechanisms contribute to the impressive adaptability of macropinocytosis in many cells and tissues and in disease.
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Affiliation(s)
- Jennifer L Stow
- Institute for Molecular Bioscience (IMB), The University of Queensland, Brisbane, QLD 4072, Australia.
| | - Yu Hung
- Institute for Molecular Bioscience (IMB), The University of Queensland, Brisbane, QLD 4072, Australia
| | - Adam A Wall
- Institute for Molecular Bioscience (IMB), The University of Queensland, Brisbane, QLD 4072, Australia
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19
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Tong SJ, Wall AA, Hung Y, Luo L, Stow JL. Guanine nucleotide exchange factors activate Rab8a for Toll-like receptor signalling. Small GTPases 2019; 12:27-43. [PMID: 30843452 DOI: 10.1080/21541248.2019.1587278] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Macrophages are important immune sentinels that detect and clear pathogens and initiate inflammatory responses through the activation of surface receptors, including Toll-like receptors (TLRs). Activated TLRs employ complex cellular trafficking and signalling pathways to initiate transcription for inflammatory cytokine programs. We have previously shown that Rab8a is activated by multiple TLRs and regulates downstream Akt/mTOR signalling by recruiting the effector PI3Kγ, but the guanine nucleotide exchange factors (GEF) canonically required for Rab8a activation in TLR pathways is not known. Using GST affinity pull-downs and mass spectrometry analysis, we identified a Rab8 specific GEF, GRAB, as a Rab8a binding partner in LPS-activated macrophages. Co-immunoprecipitation and fluorescence microscopy showed that both GRAB and a structurally similar GEF, Rabin8, undergo LPS-inducible binding to Rab8a and are localised on cell surface ruffles and macropinosomes where they coincide with sites of Rab8a mediated signalling. Rab nucleotide activation assays with CRISPR-Cas9 mediated knock-out (KO) cell lines of GRAB, Rabin8 and double KOs showed that both GEFs contribute to TLR4 induced Rab8a GTP loading, but not membrane recruitment. In addition, measurement of signalling profiles and live cell imaging with the double KOs revealed that either GEF is individually sufficient to mediate PI3Kγ-dependent Akt/mTOR signalling at macropinosomes during TLR4-driven inflammation, suggesting a redundant relationship between these proteins. Thus, both GRAB and Rabin8 are revealed as key positive regulators of Rab8a nucleotide exchange for TLR signalling and inflammatory programs. These GEFs may be useful as potential targets for manipulating inflammation. Abbreviations: TLR: Toll-like Receptor; OCRL: oculocerebrorenal syndrome of Lowe protein; PI3Kγ: phosphoinositol-3-kinase gamma; LPS: lipopolysaccharide; GEF: guanine nucleotide exchange factor; GST: glutathione S-transferases; BMMs: bone marrow derived macrophages; PH: pleckstrin homology; GAP: GTPase activating protein; ABCA1: ATP binding cassette subfamily A member 1; GDI: GDP dissociation inhibitor; LRP1: low density lipoprotein receptor-related protein 1.
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Affiliation(s)
- Samuel J Tong
- Institute for Molecular Bioscience (IMB) and IMB Centre for Inflammation and Disease Research (CIDR), The University of Queensland , Brisbane, QLD, Australia
| | - Adam A Wall
- Institute for Molecular Bioscience (IMB) and IMB Centre for Inflammation and Disease Research (CIDR), The University of Queensland , Brisbane, QLD, Australia
| | - Yu Hung
- Institute for Molecular Bioscience (IMB) and IMB Centre for Inflammation and Disease Research (CIDR), The University of Queensland , Brisbane, QLD, Australia
| | - Lin Luo
- Institute for Molecular Bioscience (IMB) and IMB Centre for Inflammation and Disease Research (CIDR), The University of Queensland , Brisbane, QLD, Australia
| | - Jennifer L Stow
- Institute for Molecular Bioscience (IMB) and IMB Centre for Inflammation and Disease Research (CIDR), The University of Queensland , Brisbane, QLD, Australia
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20
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Swanson JA, King JS. The breadth of macropinocytosis research. Philos Trans R Soc Lond B Biol Sci 2019; 374:20180146. [PMID: 30967000 PMCID: PMC6304736 DOI: 10.1098/rstb.2018.0146] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/09/2018] [Indexed: 11/12/2022] Open
Affiliation(s)
- Joel A. Swanson
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109-5620, USA
| | - Jason S. King
- Department of Biomedical Sciences, University of Sheffield, Sheffield S10 2TT, UK
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