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James EC, Tomaskovic-Crook E, Crook JM. Engineering 3D Scaffold-Free Nanoparticle-Laden Stem Cell Constructs for Piezoelectric Enhancement of Human Neural Tissue Formation and Function. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2310010. [PMID: 39049737 DOI: 10.1002/advs.202310010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 07/04/2024] [Indexed: 07/27/2024]
Abstract
Electrical stimulation (ES) of cellular systems can be utilized for biotechnological applications and electroceuticals (bioelectric medicine). Neural cell stimulation especially has a long history in neuroscience research and is increasingly applied for clinical therapies. Application of ES via conventional electrodes requires external connectors and power sources, hindering scientific and therapeutic applications. Here engineering novel 3D scaffold-free human neural stem cell constructs with integrated piezoelectric nanoparticles for enhanced neural tissue induction and function is described. Tetragonal barium titanate (BaTi03) nanoparticles are employed as piezoelectric stimulators prepared as cytocompatible dispersions, incorporated into 3D self-organizing neural spheroids, and activated wirelessly by ultrasound. Ultrasound delivery (low frequency; 40 kHz) is optimized for cell survival, and nanoparticle activation enabled ES throughout the spheroids during differentiation, tissue formation, and maturation. The resultant human neural tissues represent the first example of direct tissue loading with piezoelectric particles for ensuing 3D ultrasound-mediated piezoelectric enhancement of human neuronal induction from stem cells, including augmented neuritogenesis and synaptogenesis. It is anticipated that the platform described will facilitate advanced tissue engineering and in vitro modeling of human neural (and potentially non-neural) tissues, with modeling including tissue development and pathology, and applicable to preclinical testing and prototyping of both electroceuticals and pharmaceuticals.
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Affiliation(s)
- Emma Claire James
- ARC Centre of Excellence for Electromaterials Science, Intelligent Polymer Research Institute, AIIM Facility, University of Wollongong, Fairy Meadow, NSW, 2519, Australia
- Arto Hardy Family Biomedical Innovation Hub, Chris O'Brien Lifehouse, Camperdown, NSW, 2050, Australia
| | - Eva Tomaskovic-Crook
- ARC Centre of Excellence for Electromaterials Science, Intelligent Polymer Research Institute, AIIM Facility, University of Wollongong, Fairy Meadow, NSW, 2519, Australia
- Arto Hardy Family Biomedical Innovation Hub, Chris O'Brien Lifehouse, Camperdown, NSW, 2050, Australia
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW, 2006, Australia
| | - Jeremy Micah Crook
- ARC Centre of Excellence for Electromaterials Science, Intelligent Polymer Research Institute, AIIM Facility, University of Wollongong, Fairy Meadow, NSW, 2519, Australia
- Arto Hardy Family Biomedical Innovation Hub, Chris O'Brien Lifehouse, Camperdown, NSW, 2050, Australia
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW, 2006, Australia
- Institute of Innovative Materials, AIIM Facility, Innovation Campus, Faculty of Engineering and Information Systems, University of Wollongong, Fairy Meadow, NSW, 2519, Australia
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2
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Wang S, Ma S, Li H, Dao M, Li X, Karniadakis GE. Two-component macrophage model for active phagocytosis with pseudopod formation. Biophys J 2024; 123:1069-1084. [PMID: 38532625 PMCID: PMC11079866 DOI: 10.1016/j.bpj.2024.03.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 11/20/2023] [Accepted: 03/21/2024] [Indexed: 03/28/2024] Open
Abstract
Macrophage phagocytosis is critical for the immune response, homeostasis regulation, and tissue repair. This intricate process involves complex changes in cell morphology, cytoskeletal reorganization, and various receptor-ligand interactions controlled by mechanical constraints. However, there is a lack of comprehensive theoretical and computational models that investigate the mechanical process of phagocytosis in the context of cytoskeletal rearrangement. To address this issue, we propose a novel coarse-grained mesoscopic model that integrates a fluid-like cell membrane and a cytoskeletal network to study the dynamic phagocytosis process. The growth of actin filaments results in the formation of long and thin pseudopods, and the initial cytoskeleton can be disassembled upon target entry and reconstructed after phagocytosis. Through dynamic changes in the cytoskeleton, our macrophage model achieves active phagocytosis by forming a phagocytic cup utilizing pseudopods in two distinct ways. We have developed a new algorithm for modifying membrane area to prevent membrane rupture and ensure sufficient surface area during phagocytosis. In addition, the bending modulus, shear stiffness, and cortical tension of the macrophage model are investigated through computation of the axial force for the tubular structure and micropipette aspiration. With this model, we simulate active phagocytosis at the cytoskeletal level and investigate the mechanical process during the dynamic interplay between macrophage and target particles.
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Affiliation(s)
- Shuo Wang
- Department of Engineering Mechanics and Center for X-Mechanics, Zhejiang University, Hangzhou, Zhejiang, China
| | - Shuhao Ma
- Department of Engineering Mechanics and Center for X-Mechanics, Zhejiang University, Hangzhou, Zhejiang, China
| | - He Li
- School of Chemical, Materials and Biomedical Engineering, University of Georgia, Athens, Georgia
| | - Ming Dao
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Xuejin Li
- Department of Engineering Mechanics and Center for X-Mechanics, Zhejiang University, Hangzhou, Zhejiang, China.
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3
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Uribe-Querol E, Rosales C. Phagocytosis. Methods Mol Biol 2024; 2813:39-64. [PMID: 38888769 DOI: 10.1007/978-1-0716-3890-3_3] [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: 06/20/2024]
Abstract
One hundred years have passed since the death of Élie Metchnikoff (1845-1916). He was the first to observe the uptake of particles by cells and realized the importance of this process, named phagocytosis, for the host response to injury and infection. He also was a strong advocate of the role of phagocytosis in cellular immunity, and with this, he gave us the basis for our modern understanding of inflammation and the innate immune response. Phagocytosis is an elegant but complex process for the ingestion and elimination of pathogens, but it is also important for the elimination of apoptotic cells and hence fundamental for tissue homeostasis. Phagocytosis can be divided into four main steps: (i) recognition of the target particle, (ii) signaling to activate the internalization machinery, (iii) phagosome formation, and (iv) phagolysosome maturation. In this chapter, we present a general view of our current knowledge on phagocytosis performed mainly by professional phagocytes through antibody and complement receptors and discuss aspects that remain incompletely understood.
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Affiliation(s)
- Eileen Uribe-Querol
- Laboratorio de Biología del Desarrollo, División de Estudios de Posgrado e Investigación, Facultad de Odontología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Carlos Rosales
- Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México, Mexico.
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Zhu X, Zhao Y, Liu Y, Shi W, Yang J, Liu Z, Zhang X. Macrophages release IL11-containing filopodial tip vesicles and contribute to renal interstitial inflammation. Cell Commun Signal 2023; 21:293. [PMID: 37853428 PMCID: PMC10585809 DOI: 10.1186/s12964-023-01327-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 09/19/2023] [Indexed: 10/20/2023] Open
Abstract
Macrophage filopodia, which are dynamic nanotube-like protrusions, have mainly been studied in the context of pathogen clearance. The mechanisms by which they facilitate intercellular communication and mediate tissue inflammation remain poorly understood. Here, we show that macrophage filopodia produce a unique membrane structure called "filopodial tip vesicle" (FTV) that originate from the tip of macrophages filopodia. Filopodia tip-derived particles contain numerous internal-vesicles and function as cargo storage depots via nanotubular transport. Functional studies indicate that the shedding of FTV from filopodia tip allows the delivery of many molecular signalling molecules to fibroblasts. We observed that FTV derived from M1 macrophages and high glucose (HG)-stimulated macrophages (HG/M1-ftv) exhibit an enrichment of the chemokine IL11, which is critical for fibroblast transdifferentiation. HG/M1-ftv induce renal interstitial fibrosis in diabetic mice, while FTV inhibition or targeting FTV IL11- alleviates renal interstitial fibrosis, suggesting that the HG/M1-ftvIL11 pathway may be a novel mechanism underlying renal fibrosis in diabetic nephropathy. Collectively, FTV release could represent a novel function by which filopodia contribute to cell biological processes, and FTV is potentially associated with macrophage filopodia-related fibrotic diseases. Video Abstract.
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Affiliation(s)
- Xiaodong Zhu
- Institute of Nephrology, Zhong Da Hospital, Southeast University School of Medicine, Nanjing, Jiangsu, China
| | - Yu Zhao
- Institute of Nephrology, Zhong Da Hospital, Southeast University School of Medicine, Nanjing, Jiangsu, China
| | - Yuqiu Liu
- Institute of Nephrology, Zhong Da Hospital, Southeast University School of Medicine, Nanjing, Jiangsu, China
| | - Wen Shi
- Institute of Nephrology, Zhong Da Hospital, Southeast University School of Medicine, Nanjing, Jiangsu, China
| | - Junlan Yang
- Institute of Nephrology, Zhong Da Hospital, Southeast University School of Medicine, Nanjing, Jiangsu, China
| | - Zhihong Liu
- Jinling Hospital, National Clinical Research Center of Kidney Diseases, Nanjing University School of Medicine, Nanjing, Jiangsu, China
| | - Xiaoliang Zhang
- Institute of Nephrology, Zhong Da Hospital, Southeast University School of Medicine, Nanjing, Jiangsu, China.
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Rynikova M, Adamkova P, Hradicka P, Stofilova J, Harvanova D, Matejova J, Demeckova V. Transcriptomic Analysis of Macrophage Polarization Protocols: Vitamin D 3 or IL-4 and IL-13 Do Not Polarize THP-1 Monocytes into Reliable M2 Macrophages. Biomedicines 2023; 11:biomedicines11020608. [PMID: 36831144 PMCID: PMC9953291 DOI: 10.3390/biomedicines11020608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 02/09/2023] [Accepted: 02/16/2023] [Indexed: 02/22/2023] Open
Abstract
Two main types of macrophages (Mφ) include inflammatory (M1) and anti-inflammatory (M2) macrophages. These cells can be obtained in vitro by polarization of monocytic cell lines using various stimuli. Since there is currently no consensus on the best method for the acquisition of reliable M1 and M2 macrophages from the THP-1 cell line, we decided to compare three different polarization protocols at the transcriptomic level. Whole transcriptomes of Mφ polarized according to the chosen protocols were analyzed using RNA-seq. Differential expression of genes and functional enrichment for gene ontology terms were assessed. Compared with other protocols, M1 macrophages polarized using PMA (61.3 ng/mL) and IFN-γ along with LPS had the highest expression of M1-associated regulatory genes and genes for M1 cytokines and chemokines. According to the GO enrichment analysis, genes involved in defensive and inflammatory processes were differentially expressed in these Mφ. However, all three chosen protocols which use Vit D3, IL-13/IL-4, and IL-4, respectively, failed to promote the polarization of macrophages with a reliable M2 phenotype. Therefore, optimization or development of a new M2 polarization protocol is needed to achieve macrophages with a reliable anti-inflammatory phenotype.
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Affiliation(s)
- Maria Rynikova
- Department of Animal Physiology, Faculty of Science, Pavol Jozef Safarik University in Kosice, 041 54 Kosice, Slovakia
| | - Petra Adamkova
- Department of Animal Physiology, Faculty of Science, Pavol Jozef Safarik University in Kosice, 041 54 Kosice, Slovakia
| | - Petra Hradicka
- Department of Animal Physiology, Faculty of Science, Pavol Jozef Safarik University in Kosice, 041 54 Kosice, Slovakia
- Faculty of Medicine, Institute of Clinical Medicine, University of Oslo, 0318 Oslo, Norway
| | - Jana Stofilova
- Center of Clinical and Preclinical Research MEDIPARK, Faculty of Medicine, Pavol Jozef Safarik University in Kosice, 040 11 Kosice, Slovakia
| | - Denisa Harvanova
- Associated Tissue Bank, Faculty of Medicine, Pavol Jozef Safarik University in Kosice, 040 11 Kosice, Slovakia
| | - Jana Matejova
- Associated Tissue Bank, Faculty of Medicine, Pavol Jozef Safarik University in Kosice, 040 11 Kosice, Slovakia
| | - Vlasta Demeckova
- Department of Animal Physiology, Faculty of Science, Pavol Jozef Safarik University in Kosice, 041 54 Kosice, Slovakia
- Correspondence:
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6
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Michiels R, Gensch N, Erhard B, Rohrbach A. Pulling, failing, and adaptive mechanotransduction of macrophage filopodia. Biophys J 2022; 121:3224-3241. [PMID: 35927956 PMCID: PMC9463700 DOI: 10.1016/j.bpj.2022.07.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 07/05/2022] [Accepted: 07/21/2022] [Indexed: 11/21/2022] Open
Abstract
Macrophages use filopodia to withdraw particles toward the cell body for phagocytosis. This can require substantial forces, which the cell generates after bio-mechanical stimuli are transmitted to the filopodium. Adaptation mechanisms to mechanical stimuli are essential for cells, but can a cell iteratively improve filopodia pulling? If so, the underlying mechanic adaptation principles organized on the protein level are unclear. Here, we tackle this problem using optically trapped 1 μm beads, which we tracked interferometrically at 1 MHz during connection to the tips of dorsal filopodia of macrophages. We observe repetitive failures while the filopodium tries to pull the bead out of the optical trap. Analyses of mean bead motions and position fluctuations on the nano-meter and microsecond scale indicate mechanical ruptures caused by a force-dependent actin-membrane connection. We found that beads are retracted three times slower under any load between 5 and 40 pN relative to the no-load transport, which has the same speed as the actin retrograde flow obtained from fluorescent speckle tracking. From this duty ratio of pulling velocities, we estimated a continuous on/off binding with τoff = 2⋅τon, with measured off times τoff = 0.1-0.5 s. Remarkably, we see a gradual increase of filopodia pulling forces from 10 to 30 pN over time and after failures, which points toward an unknown adaptation mechanism. Additionally, we see that the attachment strength and friction between the bead and filopodium tip increases under load and over time. All observations are typical for catch-bond proteins such as integrin-talin complexes. We present a mechanistic picture of adaptive mechanotransduction, which formed by the help of mathematical models for repetitive tip ruptures and reconnections. The analytic mathematical model and the stochastic computer simulations, both based on catch-bond lifetimes, confirmed our measurements. Such catch-bond characteristics could also be important for other immune cells taking up counteracting pathogens.
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Affiliation(s)
- Rebecca Michiels
- Laboratory for Bio- and Nano-Photonics, Department of Microsystems Engineering, University of Freiburg, Freiburg, Germany
| | - Nicole Gensch
- Core Facility Signalling Factory, University of Freiburg, Freiburg, Germany
| | - Birgit Erhard
- Laboratory for Bio- and Nano-Photonics, Department of Microsystems Engineering, University of Freiburg, Freiburg, Germany
| | - Alexander Rohrbach
- Laboratory for Bio- and Nano-Photonics, Department of Microsystems Engineering, University of Freiburg, Freiburg, Germany; CIBSS, Centre for Integrative Biological Signalling Studies, Freiburg, Germany.
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Kalashnikov N, Moraes C. Engineering physical microenvironments to study innate immune cell biophysics. APL Bioeng 2022; 6:031504. [PMID: 36156981 PMCID: PMC9492295 DOI: 10.1063/5.0098578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 08/22/2022] [Indexed: 12/04/2022] Open
Abstract
Innate immunity forms the core of the human body's defense system against infection, injury, and foreign objects. It aims to maintain homeostasis by promoting inflammation and then initiating tissue repair, but it can also lead to disease when dysregulated. Although innate immune cells respond to their physical microenvironment and carry out intrinsically mechanical actions such as migration and phagocytosis, we still do not have a complete biophysical description of innate immunity. Here, we review how engineering tools can be used to study innate immune cell biophysics. We first provide an overview of innate immunity from a biophysical perspective, review the biophysical factors that affect the innate immune system, and then explore innate immune cell biophysics in the context of migration, phagocytosis, and phenotype polarization. Throughout the review, we highlight how physical microenvironments can be designed to probe the innate immune system, discuss how biophysical insight gained from these studies can be used to generate a more comprehensive description of innate immunity, and briefly comment on how this insight could be used to develop mechanical immune biomarkers and immunomodulatory therapies.
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Affiliation(s)
- Nikita Kalashnikov
- Department of Chemical Engineering, McGill University, Montreal, Quebec H3A 0G4, Canada
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8
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Peters DT, Reifs A, Alonso-Caballero A, Madkour A, Waller H, Kenny B, Perez-Jimenez R, Lakey JH. Unraveling the molecular determinants of the anti-phagocytic protein cloak of plague bacteria. PLoS Pathog 2022; 18:e1010447. [PMID: 35358289 PMCID: PMC9004762 DOI: 10.1371/journal.ppat.1010447] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 04/12/2022] [Accepted: 03/16/2022] [Indexed: 12/03/2022] Open
Abstract
The pathogenic bacterium Yersina pestis is protected from macrophage engulfment by a capsule like antigen, F1, formed of long polymers of the monomer protein, Caf1. However, despite the importance of this pathogen, the mechanism of protection was not understood. Here we demonstrate how F1 protects the bacteria from phagocytosis. First, we show that Escherichia coli expressing F1 showed greatly reduced adherence to macrophages. Furthermore, the few cells that did adhere remained on the macrophage surface and were not engulfed. We then inserted, by mutation, an “RGDS” integrin binding motif into Caf1. This did not change the number of cells adhering to macrophages but increased the fraction of adherent cells that were engulfed. Therefore, F1 protects in two separate ways, reducing cell adhesion, possibly by acting as a polymer brush, and hiding innate receptor binding sites needed for engulfment. F1 is very robust and we show that E. coli expressing weakened mutant polymers are engulfed like the RGDS mutant. This suggests that innate attachment sites on the native cell surface are exposed if F1 is weakened. Single-molecule force spectroscopy (SMFS) experiments revealed that wild-type F1 displays a very high mechanical stability of 400 pN. However, the mechanical resistance of the destabilised mutants, that were fully engulfed, was only 20% weaker. By only marginally exceeding the mechanical force applied to the Caf1 polymer during phagocytosis it may be that the exceptional tensile strength evolved to resist the forces applied at this stage of engulfment. Macrophages, a type of white blood cell, form an important element of our immune defence. They interrogate other cells’ surfaces for molecular clues and ingest those presenting a threat in a process known as phagocytosis. Not surprisingly, pathogenic bacteria have developed ways to evade this fate. The plague bacterium, Yersinia pestis, produces the long polymeric F1 coat protein which enables it to avoid ingestion, but the mechanism was unclear. We show that equipping Escherichia coli cells with an F1 coat protected them from phagocytosis by two separate mechanisms, reducing contact with the macrophage surface and hiding the signals that tell the macrophages they are targets. F1 is also a very stable protein polymer and using single molecule force spectroscopy we showed it also has a very high resistance to pulling forces. Surprisingly, mutations which reduced this by only 20% caused adherent bacteria to be fully ingested, indicating that cells are subject to significant forces prior to recognition and ingestion. Thus, F1 has evolved three notable properties (i) physical; creation of a hydrated polymer brush to inhibit surface interactions, (ii) chemical; absence of molecular recognition clues needed for engulfment and (iii) mechanical; strength that maintains the camouflage layer during surface stretching.
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Affiliation(s)
- Daniel T. Peters
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | | | | | - Azzeldin Madkour
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Helen Waller
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Brendan Kenny
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Raul Perez-Jimenez
- CIC nanoGUNE BRTA, San Sebastian, Spain
- Ikerbasque Foundation for Science, Bilbao, Spain
| | - Jeremy H. Lakey
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
- * E-mail:
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The Two Sweet Sides of Janus Lectin Drive Crosslinking of Liposomes to Cancer Cells and Material Uptake. Toxins (Basel) 2021; 13:toxins13110792. [PMID: 34822576 PMCID: PMC8620536 DOI: 10.3390/toxins13110792] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 11/01/2021] [Accepted: 11/04/2021] [Indexed: 12/13/2022] Open
Abstract
A chimeric, bispecific Janus lectin has recently been engineered with different, rationally oriented recognition sites. It can bind simultaneously to sialylated and fucosylated glycoconjugates. Because of its multivalent architecture, this lectin reaches nanomolar avidities for sialic acid and fucose. The lectin was designed to detect hypersialylation—a dysregulation in physiological glycosylation patterns, which promotes the tumor growth and progression of several cancer types. In this study, the characteristic properties of this bispecific Janus lectin were investigated on human cells by flow cytometry and confocal microscopy in order to understand the fundamentals of its interactions. We evaluated its potential in targeted drug delivery, precisely leading to the cellular uptake of liposomal content in human epithelial cancer cells. We successfully demonstrated that Janus lectin mediates crosslinking of glyco-decorated giant unilamellar vesicles (GUVs) and H1299 lung epithelial cells. Strikingly, the Janus lectin induced the internalization of liposomal lipids and also of complete GUVs. Our findings serve as a solid proof of concept for lectin-mediated targeted drug delivery using glyco-decorated liposomes as possible drug carriers to cells of interest. The use of Janus lectin for tumor recognition certainly broadens the possibilities for engineering diverse tailor-made lectin constructs, specifically targeting extracellular structures of high significance in pathological conditions.
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Woitzik P, Linder S. Molecular Mechanisms of Borrelia burgdorferi Phagocytosis and Intracellular Processing by Human Macrophages. BIOLOGY 2021; 10:567. [PMID: 34206480 PMCID: PMC8301104 DOI: 10.3390/biology10070567] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 06/16/2021] [Accepted: 06/20/2021] [Indexed: 12/21/2022]
Abstract
Lyme disease is the most common vector-borne illness in North America and Europe. Its causative agents are spirochetes of the Borrelia burgdorferi sensu latu complex. Infection with borreliae can manifest in different tissues, most commonly in the skin and joints, but in severe cases also in the nervous systems and the heart. The immune response of the host is a crucial factor for preventing the development or progression of Lyme disease. Macrophages are part of the innate immune system and thus one of the first cells to encounter infecting borreliae. As professional phagocytes, they are capable of recognition, uptake, intracellular processing and final elimination of borreliae. This sequence of events involves the initial capture and internalization by actin-rich cellular protrusions, filopodia and coiling pseudopods. Uptake into phagosomes is followed by compaction of the elongated spirochetes and degradation in mature phagolysosomes. In this review, we discuss the current knowledge about the processes and molecular mechanisms involved in recognition, capturing, uptake and intracellular processing of Borrelia by human macrophages. Moreover, we highlight interactions between macrophages and other cells of the immune system during these processes and point out open questions in the intracellular processing of borreliae, which include potential escape strategies of Borrelia.
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Affiliation(s)
| | - Stefan Linder
- Institute for Medical Microbiology, Virology and Hygiene, University Medical Center Eppendorf, 20246 Hamburg, Germany;
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Cicuéndez M, Casarrubios L, Feito MJ, Madarieta I, Garcia-Urkia N, Murua O, Olalde B, Briz N, Diez-Orejas R, Portolés MT. Candida albicans/Macrophage Biointerface on Human and Porcine Decellularized Adipose Matrices. J Fungi (Basel) 2021; 7:jof7050392. [PMID: 34067785 PMCID: PMC8156393 DOI: 10.3390/jof7050392] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 05/12/2021] [Accepted: 05/15/2021] [Indexed: 12/20/2022] Open
Abstract
Macrophages, cells effective in sensing, internalizing and killing Candida albicans, are intertwined with the extracellular matrix (ECM) through different signals, which include the release of specific cytokines. Due to the importance of these interactions, the employment of in vitro models mimicking a fungal infection scenario is essential to evaluate the ECM effects on the macrophage response. In this work, we have analyzed the effects of human and porcine decellularized adipose matrices (DAMs), obtained by either enzymatic or organic solvent treatment, on the macrophage/Candida albicans interface. The present study has allowed us to detect differences on the activation of macrophages cultured on either human- or porcine-derived DAMs, evidencing changes in the macrophage actin cytoskeleton, such as distinct F-actin-rich membrane structures to surround the pathogen. The macrophage morphological changes observed on these four DAMs are key to understand the defense capability of these cells against this fungal pathogen. This work has contributed to the knowledge of the influence that the extracellular matrix and its components can exert on macrophage metabolism, immunocompetence and capacity to respond to the microenvironment in a possible infection scenario.
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Affiliation(s)
- Mónica Cicuéndez
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Universidad Complutense de Madrid, 28040 Madrid, Spain; (M.C.); (L.C.); (M.J.F.)
| | - Laura Casarrubios
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Universidad Complutense de Madrid, 28040 Madrid, Spain; (M.C.); (L.C.); (M.J.F.)
| | - María José Feito
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Universidad Complutense de Madrid, 28040 Madrid, Spain; (M.C.); (L.C.); (M.J.F.)
| | - Iratxe Madarieta
- TECNALIA, Basque Research and Technology Alliance (BRTA), E20009 Donostia-San Sebastian, Spain; (I.M.); (N.G.-U.); (O.M.); (N.B.)
| | - Nerea Garcia-Urkia
- TECNALIA, Basque Research and Technology Alliance (BRTA), E20009 Donostia-San Sebastian, Spain; (I.M.); (N.G.-U.); (O.M.); (N.B.)
| | - Olatz Murua
- TECNALIA, Basque Research and Technology Alliance (BRTA), E20009 Donostia-San Sebastian, Spain; (I.M.); (N.G.-U.); (O.M.); (N.B.)
| | - Beatriz Olalde
- TECNALIA, Basque Research and Technology Alliance (BRTA), E20009 Donostia-San Sebastian, Spain; (I.M.); (N.G.-U.); (O.M.); (N.B.)
- Correspondence: (B.O.); (R.D.-O.); (M.T.P.)
| | - Nerea Briz
- TECNALIA, Basque Research and Technology Alliance (BRTA), E20009 Donostia-San Sebastian, Spain; (I.M.); (N.G.-U.); (O.M.); (N.B.)
| | - Rosalía Diez-Orejas
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid, 28040 Madrid, Spain
- Correspondence: (B.O.); (R.D.-O.); (M.T.P.)
| | - María Teresa Portolés
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Universidad Complutense de Madrid, 28040 Madrid, Spain; (M.C.); (L.C.); (M.J.F.)
- CIBER de Bioingeniería, Biomateriales y Nanomedicina, CIBER-BBN, 28040 Madrid, Spain
- Correspondence: (B.O.); (R.D.-O.); (M.T.P.)
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12
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Vorselen D, Labitigan RLD, Theriot JA. A mechanical perspective on phagocytic cup formation. Curr Opin Cell Biol 2020; 66:112-122. [PMID: 32698097 DOI: 10.1016/j.ceb.2020.05.011] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Revised: 05/26/2020] [Accepted: 05/30/2020] [Indexed: 12/23/2022]
Abstract
Phagocytosis is a widespread and evolutionarily conserved process with diverse biological functions, ranging from engulfment of invading microbes during infection to clearance of apoptotic debris in tissue homeostasis. Along with differences in biochemical composition, phagocytic targets greatly differ in physical attributes, such as size, shape, and rigidity, which are now recognized as important regulators of this process. Force exertion at the cell-target interface and cellular mechanical changes during phagocytosis are emerging as crucial factors underlying sensing of such target properties. With technological developments, mechanical aspects of phagocytosis are increasingly accessible experimentally, revealing remarkable organizational complexity of force exertion. An increasingly high-resolution picture is emerging of how target physical cues and cellular mechanical properties jointly govern important steps throughout phagocytic engulfment.
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Affiliation(s)
- Daan Vorselen
- Department of Biology, University of Washington, Seattle, WA 98105, USA
| | - Ramon Lorenzo D Labitigan
- Department of Biology, University of Washington, Seattle, WA 98105, USA; Department of Biochemistry, Stanford University, Stanford, CA 94305, USA
| | - Julie A Theriot
- Department of Biology, University of Washington, Seattle, WA 98105, USA; Howard Hughes Medical Institute, University of Washington, Seattle, WA 98105, USA.
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13
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Richards DM. Receptor Models of Phagocytosis: The Effect of Target Shape. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1246:55-70. [PMID: 32399825 DOI: 10.1007/978-3-030-40406-2_4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Phagocytosis is a remarkably complex process, requiring simultaneous organisation of the cell membrane, the cytoskeleton, receptors and various signalling molecules. As can often be the case, mathematical modelling is able to penetrate some of this complexity, identifying the key biophysical components and generating understanding that would take far longer with a purely experimental approach. This chapter will review a particularly important class of phagocytosis model, championed in recent years, that primarily focuses on the role of receptors during the engulfment process. These models are pertinent to a host of unsolved questions in the subject, including the rate of cup growth during uptake, the role of both intra- and extracellular noise, and the precise differences between phagocytosis and other forms of endocytosis. In particular, this chapter will focus on the effect of target shape and orientation, including how these influence the rate and final outcome of phagocytic engulfment.
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14
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Jain N, Moeller J, Vogel V. Mechanobiology of Macrophages: How Physical Factors Coregulate Macrophage Plasticity and Phagocytosis. Annu Rev Biomed Eng 2020; 21:267-297. [PMID: 31167103 DOI: 10.1146/annurev-bioeng-062117-121224] [Citation(s) in RCA: 137] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In addition to their early-recognized functions in host defense and the clearance of apoptotic cell debris, macrophages play vital roles in tissue development, homeostasis, and repair. If misregulated, they steer the progression of many inflammatory diseases. Much progress has been made in understanding the mechanisms underlying macrophage signaling, transcriptomics, and proteomics, under physiological and pathological conditions. Yet, the detailed mechanisms that tune circulating monocytes/macrophages and tissue-resident macrophage polarization, differentiation, specification, and their functional plasticity remain elusive. We review how physical factors affect macrophage phenotype and function, including how they hunt for particles and pathogens, as well as the implications for phagocytosis, autophagy, and polarization from proinflammatory to prohealing phenotype. We further discuss how this knowledge can be harnessed in regenerative medicine and for the design of new drugs and immune-modulatory drug delivery systems, biomaterials, and tissue scaffolds.
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Affiliation(s)
- Nikhil Jain
- Laboratory of Applied Mechanobiology, Institute of Translational Medicine, and Department of Health Sciences and Technology, ETH Zurich, CH-8093 Zurich, Switzerland;
| | - Jens Moeller
- Laboratory of Applied Mechanobiology, Institute of Translational Medicine, and Department of Health Sciences and Technology, ETH Zurich, CH-8093 Zurich, Switzerland;
| | - Viola Vogel
- Laboratory of Applied Mechanobiology, Institute of Translational Medicine, and Department of Health Sciences and Technology, ETH Zurich, CH-8093 Zurich, Switzerland;
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15
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Gao P, Mu M, Chen Y, He J, Tao X, Song C. Yes-associated protein upregulates filopodia formation to promote alveolar epithelial-cell phagocytosis. Immunol Lett 2020; 225:44-49. [PMID: 32554050 DOI: 10.1016/j.imlet.2020.06.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 06/10/2020] [Accepted: 06/11/2020] [Indexed: 02/08/2023]
Abstract
Cells engulf particles larger than 0.5 μm in diameter by phagocytosis, which is driven by cytoskeletal rearrangements. Phagocytosis by alveolar epithelial cells (AECs) helps to maintain the alveolar homeostasis. Yes-associated protein (YAP), a transcriptional coactivator of the Hippo pathway, affects proliferation, differentiation, and cytoskeletal rearrangement of AECs, but it is not clear whether YAP regulates phagocytosis. In this study, interference with YAP expression inhibited phagocytosis in MLE-12 cells and in primary cultures of AEC. Filopodia formation promoted phagocytosis in AECs, and YAP enhanced filopodia formation in AECs. Blocking PI3K signaling resulted in reduced YAP protein expression and inhibition of phagocytosis. The results indicate that YAP expression was regulated by PI3K signaling and promoted phagocytosis in AECs by upregulating filopodia formation.
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Affiliation(s)
- Peiyu Gao
- Department of Immunology, School of Laboratory Medicine, Bengbu Medical College, Anhui, 233030, PR China; Anhui Provincial Key Laboratory of Infection and Immunity, Bengbu Medical College, Bengbu, Anhui, 233030, PR China; Anhui Province Key Laboratory of Immunology in Chronic Diseases, Bengbu Medical College, Bengbu, Anhui, 233030, PR China
| | - Mimi Mu
- Department of Immunology, School of Laboratory Medicine, Bengbu Medical College, Anhui, 233030, PR China; Anhui Provincial Key Laboratory of Infection and Immunity, Bengbu Medical College, Bengbu, Anhui, 233030, PR China; Anhui Province Key Laboratory of Immunology in Chronic Diseases, Bengbu Medical College, Bengbu, Anhui, 233030, PR China
| | - Yan Chen
- Department of Immunology, School of Laboratory Medicine, Bengbu Medical College, Anhui, 233030, PR China; Anhui Provincial Key Laboratory of Infection and Immunity, Bengbu Medical College, Bengbu, Anhui, 233030, PR China; Anhui Province Key Laboratory of Immunology in Chronic Diseases, Bengbu Medical College, Bengbu, Anhui, 233030, PR China
| | - Jing He
- Department of Immunology, School of Laboratory Medicine, Bengbu Medical College, Anhui, 233030, PR China; Anhui Provincial Key Laboratory of Infection and Immunity, Bengbu Medical College, Bengbu, Anhui, 233030, PR China; Anhui Province Key Laboratory of Immunology in Chronic Diseases, Bengbu Medical College, Bengbu, Anhui, 233030, PR China
| | - Xiangnan Tao
- Clinical Laboratory, The Second Affiliated Hospital of Bengbu Medical College, Anhui, 233004, PR China
| | - Chuanwang Song
- Department of Immunology, School of Laboratory Medicine, Bengbu Medical College, Anhui, 233030, PR China; Anhui Provincial Key Laboratory of Infection and Immunity, Bengbu Medical College, Bengbu, Anhui, 233030, PR China; Anhui Province Key Laboratory of Immunology in Chronic Diseases, Bengbu Medical College, Bengbu, Anhui, 233030, PR China.
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16
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Lin J, Shi Y, Men Y, Wang X, Ye J, Zhang C. Mechanical Roles in Formation of Oriented Collagen Fibers. TISSUE ENGINEERING PART B-REVIEWS 2020; 26:116-128. [PMID: 31801418 DOI: 10.1089/ten.teb.2019.0243] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Collagen is a structural protein that is widely present in vertebrates, being usually distributed in tissues in the form of fibers. In living organisms, fibers are organized in different orientations in various tissues. As the structural base in connective tissue and load-bearing tissue, the orientation of collagen fibers plays an extremely important role in the mechanical properties and physiological and biochemical functions. The study on mechanics role in formation of oriented collagen fibers enables us to understand how discrete cells use limited molecular materials to create tissues with different structures, thereby promoting our understanding of the mechanism of tissue formation from scratch, from invisible to tangible. However, the current understanding of the mechanism of fiber orientation is still insufficient. In addition, existing fabrication methods of oriented fibers are varied and involve interdisciplinary study, and the achievements of each experiment are favorable to the construction and improvement of the fiber orientation theory. To this end, this review focuses on the preparation methods of oriented fibers and proposes a model explaining the formation process of oriented fibers in tendons based on the existing fiber theory. Impact statement As the structural base in connective tissue and load-bearing tissue, the orientation of collagen fibers plays an extremely important role in the mechanical properties and physiological and biochemical functions. However, the current understanding of the mechanism of fiber orientation is still insufficient, which is greatly responsible for the challenge of functional tissue repair and regeneration. Understanding the mechanism of fiber orientation can promote the successful application of fiber orientation scaffolds in tissue repair and regeneration, as well as providing an insight for the mechanism of tissue histomorphology.
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Affiliation(s)
- Jiexiang Lin
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, P.R. China
| | - Yanping Shi
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, P.R. China
| | - Yutao Men
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, P.R. China
| | - Xin Wang
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, P.R. China
| | - Jinduo Ye
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, P.R. China
| | - Chunqiu Zhang
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, P.R. China
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17
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Mularski A, Niedergang F. Force Measurement of Living Professional Phagocytes of the Immune System. Aust J Chem 2020. [DOI: 10.1071/ch19409] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
In higher organisms, the professional phagocytes of the immune system (dendritic cells, neutrophils, monocytes, and macrophages) are responsible for pathogen clearance, the development of immune responses via cytokine secretion and presentation of antigens derived from internalized material, and the normal turnover and remodelling of tissues and disposal of dead cells. These functions rely on the ability of phagocytes to migrate and adhere to sites of infection, dynamically probe their environments to make contact with phagocytic targets, and perform phagocytosis, a mechanism of internalization of large particles, microorganisms, and cellular debris for intracellular degradation. The cell-generated forces that are necessary for the professional phagocytes to act in their roles as ‘first responders’ of the immune system have been the subject of mechanical studies in recent years. Methods of force measurement such as atomic force microscopy, traction force microscopy, micropipette aspiration, magnetic and optical tweezers, and exciting new variants of these have accompanied classical biological methods to perform mechanical investigations of these highly dynamic immune cells.
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18
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Barger SR, Gauthier NC, Krendel M. Squeezing in a Meal: Myosin Functions in Phagocytosis. Trends Cell Biol 2019; 30:157-167. [PMID: 31836280 DOI: 10.1016/j.tcb.2019.11.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 11/11/2019] [Accepted: 11/14/2019] [Indexed: 12/21/2022]
Abstract
Phagocytosis is a receptor-mediated, actin-dependent process of internalization of large extracellular particles, such as pathogens or apoptotic cells. Engulfment of phagocytic targets requires the activity of myosins, actin-dependent molecular motors, which perform a variety of functions at distinct steps during phagocytosis. By applying force to actin filaments, the plasma membrane, and intracellular proteins and organelles, myosins can generate contractility, directly regulate actin assembly to ensure proper phagocytic internalization, and translocate phagosomes or other cargo to appropriate cellular locations. Recent studies using engineered microenvironments and phagocytic targets have demonstrated how altering the actomyosin cytoskeleton affects phagocytic behavior. Here, we discuss how studies using genetic and biochemical manipulation of myosins, force measurement techniques, and live-cell imaging have advanced our understanding of how specific myosins function at individual steps of phagocytosis.
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Affiliation(s)
- Sarah R Barger
- Cell and Developmental Biology Department, State University of New York Upstate Medical University, Syracuse, NY, USA
| | | | - Mira Krendel
- Cell and Developmental Biology Department, State University of New York Upstate Medical University, Syracuse, NY, USA.
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19
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Gasilina A, Vitali T, Luo R, Jian X, Randazzo PA. The ArfGAP ASAP1 Controls Actin Stress Fiber Organization via Its N-BAR Domain. iScience 2019; 22:166-180. [PMID: 31785555 PMCID: PMC6889188 DOI: 10.1016/j.isci.2019.11.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 09/30/2019] [Accepted: 11/06/2019] [Indexed: 12/11/2022] Open
Abstract
ASAP1 is a multi-domain ArfGAP that controls cell migration, spreading, and focal adhesion dynamics. Although its GAP activity contributes to remodeling of the actin cytoskeleton, it does not fully explain all cellular functions of ASAP1. Here we find that ASAP1 regulates actin filament assembly directly through its N-BAR domain and controls stress fiber maintenance. ASAP1 depletion caused defects in stress fiber organization. Conversely, overexpression of ASAP1 enhanced actin remodeling. The BAR-PH fragment was sufficient to affect actin. ASAP1 with the BAR domain replaced with the BAR domain of the related ACAP1 did not affect actin. The BAR-PH tandem of ASAP1 bound and bundled actin filaments directly, whereas the presence of the ArfGAP and the C-terminal linker/SH3 domain reduced binding and bundling of filaments by BAR-PH. Together these data provide evidence that ASAP1 may regulate the actin cytoskeleton through direct interaction of the BAR-PH domain with actin filaments.
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Affiliation(s)
- Anjelika Gasilina
- Section on Regulation of Ras Superfamily, Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bldg. 37, Rm. 2042, Bethesda, MD 20892, USA; Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, Washington, DC 20007, USA
| | - Teresa Vitali
- Section on Regulation of Ras Superfamily, Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bldg. 37, Rm. 2042, Bethesda, MD 20892, USA
| | - Ruibai Luo
- Section on Regulation of Ras Superfamily, Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bldg. 37, Rm. 2042, Bethesda, MD 20892, USA
| | - Xiaoying Jian
- Section on Regulation of Ras Superfamily, Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bldg. 37, Rm. 2042, Bethesda, MD 20892, USA
| | - Paul A Randazzo
- Section on Regulation of Ras Superfamily, Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bldg. 37, Rm. 2042, Bethesda, MD 20892, USA.
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20
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Zhao Y, Mahajan G, Kothapalli CR, Sun XL. Sialylation status and mechanical properties of THP-1 macrophages upon LPS stimulation. Biochem Biophys Res Commun 2019; 518:573-578. [PMID: 31445704 DOI: 10.1016/j.bbrc.2019.08.089] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 08/15/2019] [Indexed: 11/20/2022]
Abstract
Cell surface receptors are the key contributors of macrophage function. Most macrophage cell surface receptors are glycoproteins with sialic acids at the terminal of their glycans. It is well recognized that lipopolysaccharide (LPS) induces cell surface sialylation changes that may in turn contribute to macrophage functions. In addition, cellular mechanics such as elasticity is also a major determinant of macrophage function, which in turn is modulated by LPS. In this report, we characterized the sialylation status of macrophages upon LPS stimulation and assessed the changes in its mechanical properties and function. Specifically, we confirmed that sialylation status is closely related to macrophage biomechanical characteristics (elastic modulus, tether force, tether radius, adhesion force, and membrane tension) and thus directly involved in macrophage function. Further, we modulated macrophage sialylation status by feeding the cell with exogenous free sialic acid (Neu5Ac, Neu5Gc) and sialidase inhibitors, and examined the resulting effects on cellular mechanics and function. A systematic recognition of sialylation status related to cellular mechanics of macrophages will contribute to defining their phenotypes and elucidate macrophage functional diversity.
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Affiliation(s)
- Yu Zhao
- Department of Chemistry and Center of Gene Regulation of Health and Disease (GRHD), Cleveland State University, Cleveland, OH, OH 44115, United States
| | - Gautam Mahajan
- Department of Chemical & Biomedical Engineering, Cleveland State University, Cleveland, OH, OH 44115, United States
| | - Chandrasekhar R Kothapalli
- Department of Chemical & Biomedical Engineering, Cleveland State University, Cleveland, OH, OH 44115, United States.
| | - Xue-Long Sun
- Department of Chemistry and Center of Gene Regulation of Health and Disease (GRHD), Cleveland State University, Cleveland, OH, OH 44115, United States; Department of Chemical & Biomedical Engineering, Cleveland State University, Cleveland, OH, OH 44115, United States.
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21
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Palankar R, Binsker U, Haracska B, Wesche J, Greinacher A, Hammerschmidt S. Interaction between the Staphylococcus aureus extracellular adherence protein Eap and its subdomains with platelets. Int J Med Microbiol 2018; 308:683-691. [DOI: 10.1016/j.ijmm.2018.04.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 03/30/2018] [Accepted: 04/14/2018] [Indexed: 12/20/2022] Open
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22
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Lillico DME, Pemberton JG, Stafford JL. Selective Regulation of Cytoskeletal Dynamics and Filopodia Formation by Teleost Leukocyte Immune-Type Receptors Differentially Contributes to Target Capture During the Phagocytic Process. Front Immunol 2018; 9:1144. [PMID: 30002653 PMCID: PMC6032007 DOI: 10.3389/fimmu.2018.01144] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 05/07/2018] [Indexed: 01/08/2023] Open
Abstract
Phagocytosis evolved from a fundamental nutrient acquisition mechanism in primitive unicellular amoeboids, into a dynamic and complex component of innate immunity in multicellular organisms. To better understand the cellular mechanisms contributing to phagocytic processes across vertebrates, our research has focused on characterizing the involvement of innate immune proteins originally identified in channel catfish (Ictalurus punctatus) called leukocyte immune-type receptors (IpLITRs). These unique teleost proteins share basic structural as well as distant phylogenetic relationships with several immunoregulatory proteins within the mammalian immunoglobulin superfamily. In the present study, we use a combination of live-cell confocal imaging and high-resolution scanning electron microscopy to further examine the classical immunoreceptor tyrosine-based activation motif (ITAM)-dependent phagocytic pathway mediated by the chimeric construct IpLITR 2.6b/IpFcRγ-L and the functionally diverse immunoreceptor tyrosine-based inhibitory motif-containing receptor IpLITR 1.1b. Results demonstrate that IpLITR 1.1b-expressing cells can uniquely generate actin-dense filopodia-like protrusions during the early stages of extracellular target interactions. In addition, we observed that these structures retract after contacting extracellular targets to secure captured microspheres on the cell surface. This activity was often followed by the generation of robust secondary waves of actin polymerization leading to the formation of stabilized phagocytic cups. At depressed temperatures of 27°C, IpLITR 2.6b/IpFcRγ-L-mediated phagocytosis was completely blocked, whereas IpLITR 1.1b-expressing cells continued to generate dynamic actin-dense filopodia at this lower temperature. Overall, these results provide new support for the hypothesis that IpLITR 1.1b, but not IpLITR 2.6b/IpFcRγ-L, directly triggers filopodia formation when expressed in representative myeloid cells. This also offers new information regarding the directed ability of immunoregulatory receptor-types to initiate dynamic membrane structures and provides insights into an alternative ITAM-independent target capture pathway that is functionally distinct from the classical phagocytic pathways.
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Affiliation(s)
- Dustin M E Lillico
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Joshua G Pemberton
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - James L Stafford
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
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23
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Byvalov AA, Kononenko VL, Konyshev IV. Single-Cell Force Spectroscopy of Interaction of Lipopolysaccharides from Yersinia pseudotuberculosis and Yersinia pestis with J774 Macrophage Membrane Using Optical Tweezers. BIOCHEMISTRY (MOSCOW), SUPPLEMENT SERIES A: MEMBRANE AND CELL BIOLOGY 2018. [DOI: 10.1134/s1990747818020058] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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24
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Richards DM, Endres RG. How cells engulf: a review of theoretical approaches to phagocytosis. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2017; 80:126601. [PMID: 28824015 DOI: 10.1088/1361-6633/aa8730] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Phagocytosis is a fascinating process whereby a cell surrounds and engulfs particles such as bacteria and dead cells. This is crucial both for single-cell organisms (as a way of acquiring nutrients) and as part of the immune system (to destroy foreign invaders). This whole process is hugely complex and involves multiple coordinated events such as membrane remodelling, receptor motion, cytoskeleton reorganisation and intracellular signalling. Because of this, phagocytosis is an excellent system for theoretical study, benefiting from biophysical approaches combined with mathematical modelling. Here, we review these theoretical approaches and discuss the recent mathematical and computational models, including models based on receptors, models focusing on the forces involved, and models employing energetic considerations. Along the way, we highlight a beautiful connection to the physics of phase transitions, consider the role of stochasticity, and examine links between phagocytosis and other types of endocytosis. We cover the recently discovered multistage nature of phagocytosis, showing that the size of the phagocytic cup grows in distinct stages, with an initial slow stage followed by a much quicker second stage starting around half engulfment. We also address the issue of target shape dependence, which is relevant to both pathogen infection and drug delivery, covering both one-dimensional and two-dimensional results. Throughout, we pay particular attention to recent experimental techniques that continue to inform the theoretical studies and provide a means to test model predictions. Finally, we discuss population models, connections to other biological processes, and how physics and modelling will continue to play a key role in future work in this area.
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Affiliation(s)
- David M Richards
- Centre for Biomedical Modelling and Analysis, Living Systems Institute, University of Exeter, Exeter, EX4 4QD, United Kingdom. Department of Life Sciences, Imperial College, London, SW7 2AZ, United Kingdom
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25
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Makama S, Kloet SK, Piella J, van den Berg H, de Ruijter NCA, Puntes VF, Rietjens IMCM, van den Brink NW. Effects of Systematic Variation in Size and Surface Coating of Silver Nanoparticles on Their In Vitro Toxicity to Macrophage RAW 264.7 Cells. Toxicol Sci 2017; 162:79-88. [DOI: 10.1093/toxsci/kfx228] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Sunday Makama
- Division of Toxicology, Wageningen University, WE 6708 Wageningen, The Netherlands
- Wageningen Environmental Research (Alterra), Wageningen University and Research, PB 6708 Wageningen, The Netherlands
| | - Samantha K Kloet
- Division of Toxicology, Wageningen University, WE 6708 Wageningen, The Netherlands
| | - Jordi Piella
- Institut Català de Nanociència i Nanotecnologia (ICN2), Campus de la Universitat Autònoma de Barcelona (Campus UAB), 08193 Bellaterra (Barcelona), Spain
| | - Hans van den Berg
- Division of Toxicology, Wageningen University, WE 6708 Wageningen, The Netherlands
| | | | - Victor F Puntes
- Institut Català de Nanociència i Nanotecnologia (ICN2), Campus de la Universitat Autònoma de Barcelona (Campus UAB), 08193 Bellaterra (Barcelona), Spain
- Vall d'Hebron Institut de Recerca (VHIR), Edificio Mediterránea, Hospital Vall d'Hebron, 08035 Barcelona, Spain
- Institut Català de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Spain
| | | | - Nico W van den Brink
- Division of Toxicology, Wageningen University, WE 6708 Wageningen, The Netherlands
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26
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Abstract
Phagocytosis refers to the active process that allows cells to take up large particulate material upon binding to surface receptors. The discovery of phagocytosis in 1883 by Elie Metchnikoff, leading to the concept that specialized cells are implicated in the defense against microbes, was one of the starting points of the field of immunology. After more than a century of research, phagocytosis is now appreciated to be a widely used process that enables the cellular uptake of a remarkable variety of particles, including bacteria, fungi, parasites, viruses, dead cells, and assorted debris and solid materials. Uptake of foreign particles is performed almost exclusively by specialized myeloid cells, commonly termed "professional phagocytes": neutrophils, monocytes, macrophages, and dendritic cells. Phagocytosis of microbes not only stops or at least restricts the spread of infection but also plays an important role in regulating the innate and adaptive immune responses. Activation of the myeloid cells upon phagocytosis leads to the secretion of cytokines and chemokines that convey signals to a variety of immune cells. Moreover, foreign antigens generated by the degradation of microbes following phagocytosis are loaded onto the major histocompatibility complex for presentation to specific T lymphocytes. However, phagocytosis is not restricted to professional myeloid phagocytes; an expanding diversity of cell types appear capable of engulfing apoptotic bodies and debris, playing a critical role in tissue remodeling and in the clearance of billions of effete cells every day.
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27
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Abstract
Phagocytes recognize and eliminate pathogens, alert other tissues of impending threats, and provide a link between innate and adaptive immunity. They also maintain tissue homeostasis, consuming dead cells without causing alarm. The receptor engagement, signal transduction, and cytoskeletal rearrangements underlying phagocytosis are paradigmatic of other immune responses and bear similarities to macropinocytosis and cell migration. We discuss how the glycocalyx restricts access to phagocytic receptors, the processes that enable receptor engagement and clustering, and the remodeling of the actin cytoskeleton that controls the mobility of membrane proteins and lipids and provides the mechanical force propelling the phagocyte membrane toward and around the phagocytic prey.
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Affiliation(s)
- Philip P Ostrowski
- Program in Cell Biology, Peter Gilgan Centre for Research & Learning, Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada; Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Sergio Grinstein
- Program in Cell Biology, Peter Gilgan Centre for Research & Learning, Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada; Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada; Keenan Research Centre of the Li Ka Shing Knowledge Institute, St. Michael's Hospital, 290 Victoria Street, Toronto, ON M5C 1N8, Canada.
| | - Spencer A Freeman
- Program in Cell Biology, Peter Gilgan Centre for Research & Learning, Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada
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28
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Phagocytosis: A Fundamental Process in Immunity. BIOMED RESEARCH INTERNATIONAL 2017; 2017:9042851. [PMID: 28691037 PMCID: PMC5485277 DOI: 10.1155/2017/9042851] [Citation(s) in RCA: 281] [Impact Index Per Article: 40.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 04/18/2017] [Indexed: 01/12/2023]
Abstract
One hundred years have passed since the death of Élie Metchnikoff (1845-1916). He was the first to observe the uptake of particles by cells and realized the importance of this process for the host response to injury and infection. He also was a strong advocate of the role of phagocytosis in cellular immunity, and with this he gave us the basis for our modern understanding of inflammation and the innate and acquired immune responses. Phagocytosis is an elegant but complex process for the ingestion and elimination of pathogens, but it is also important for the elimination of apoptotic cells and hence fundamental for tissue homeostasis. Phagocytosis can be divided into four main steps: (i) recognition of the target particle, (ii) signaling to activate the internalization machinery, (iii) phagosome formation, and (iv) phagolysosome maturation. In recent years, the use of new tools of molecular biology and microscopy has provided new insights into the cellular mechanisms of phagocytosis. In this review, we present a general view of our current knowledge on phagocytosis. We emphasize novel molecular findings, particularly on phagosome formation and maturation, and discuss aspects that remain incompletely understood.
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Horsthemke M, Bachg AC, Groll K, Moyzio S, Müther B, Hemkemeyer SA, Wedlich-Söldner R, Sixt M, Tacke S, Bähler M, Hanley PJ. Multiple roles of filopodial dynamics in particle capture and phagocytosis and phenotypes of Cdc42 and Myo10 deletion. J Biol Chem 2017; 292:7258-7273. [PMID: 28289096 DOI: 10.1074/jbc.m116.766923] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 03/13/2017] [Indexed: 12/14/2022] Open
Abstract
Macrophage filopodia, finger-like membrane protrusions, were first implicated in phagocytosis more than 100 years ago, but little is still known about the involvement of these actin-dependent structures in particle clearance. Using spinning disk confocal microscopy to image filopodial dynamics in mouse resident Lifeact-EGFP macrophages, we show that filopodia, or filopodia-like structures, support pathogen clearance by multiple means. Filopodia supported the phagocytic uptake of bacterial (Escherichia coli) particles by (i) capturing along the filopodial shaft and surfing toward the cell body, the most common mode of capture; (ii) capturing via the tip followed by retraction; (iii) combinations of surfing and retraction; or (iv) sweeping actions. In addition, filopodia supported the uptake of zymosan (Saccharomyces cerevisiae) particles by (i) providing fixation, (ii) capturing at the tip and filopodia-guided actin anterograde flow with phagocytic cup formation, and (iii) the rapid growth of new protrusions. To explore the role of filopodia-inducing Cdc42, we generated myeloid-restricted Cdc42 knock-out mice. Cdc42-deficient macrophages exhibited rapid phagocytic cup kinetics, but reduced particle clearance, which could be explained by the marked rounded-up morphology of these cells. Macrophages lacking Myo10, thought to act downstream of Cdc42, had normal morphology, motility, and phagocytic cup formation, but displayed markedly reduced filopodia formation. In conclusion, live-cell imaging revealed multiple mechanisms involving macrophage filopodia in particle capture and engulfment. Cdc42 is not critical for filopodia or phagocytic cup formation, but plays a key role in driving macrophage lamellipodial spreading.
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Affiliation(s)
- Markus Horsthemke
- From the Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Anne C Bachg
- From the Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Katharina Groll
- From the Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Sven Moyzio
- From the Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Barbara Müther
- From the Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Sandra A Hemkemeyer
- From the Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Roland Wedlich-Söldner
- the Institut für Zelldynamik und Bildgebung, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Michael Sixt
- the Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria, and
| | - Sebastian Tacke
- the Institut für Medizinische Physik und Biophysik, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Martin Bähler
- From the Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Peter J Hanley
- From the Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany,
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Davidson AJ, Wood W. Unravelling the Actin Cytoskeleton: A New Competitive Edge? Trends Cell Biol 2016; 26:569-576. [PMID: 27133808 PMCID: PMC4961066 DOI: 10.1016/j.tcb.2016.04.001] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 03/31/2016] [Accepted: 04/04/2016] [Indexed: 12/27/2022]
Abstract
Dynamic rearrangements in the actin cytoskeleton underlie a wide range of cell behaviours, which in turn contribute to many aspects of human health including embryogenesis, cancer metastasis, wound healing, and inflammation. Precise control of the actin cytoskeleton requires the coordinated activity of a diverse set of different actin regulators. However, our current understanding of the actin cytoskeleton has focused on how individual actin regulatory pathways function in isolation from one another. Recently, competition has emerged as a means by which different actin assembly factors can influence each other's activity at the cellular level. Here such findings will be used to explore the possibility that competition within the actin cytoskeleton confers cellular plasticity and the ability to prioritise multiple conflicting stimuli. Cells maintain a dynamic actin cytoskeleton by carefully balancing the activities of a diverse collection of actin regulators. Recent findings suggest that key actin assembly factors limit one another through competition over a finite pool of G-actin. Increasing or decreasing cellular G-actin influences the type of F-actin network generated. The actin monomer binding protein profilin is responsible for proportioning how much G-actin is available to each assembly factor. Cytoskeletal competition appears universally conserved from yeast to human. Competition ensures cytoskeletal homeostasis and integration/coordination between the different actin regulatory pathways to support dynamic cell behaviour.
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Affiliation(s)
- Andrew J Davidson
- School of Cellular and Molecular Medicine, Faculty of Biomedical Sciences, Biomedical Science Building, University of Bristol, University Walk, Bristol, BS8 1TD, UK
| | - Will Wood
- School of Cellular and Molecular Medicine, Faculty of Biomedical Sciences, Biomedical Science Building, University of Bristol, University Walk, Bristol, BS8 1TD, UK.
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Surfing along Filopodia: A Particle Transport Revealed by Molecular-Scale Fluctuation Analyses. Biophys J 2016; 108:2114-25. [PMID: 25954870 DOI: 10.1016/j.bpj.2015.02.029] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 02/13/2015] [Accepted: 02/23/2015] [Indexed: 01/08/2023] Open
Abstract
Filopodia perform cellular functions such as environmental sensing or cell motility, but they also grab for particles and withdraw them leading to an increased efficiency of phagocytic uptake. Remarkably, withdrawal of micron-sized particles is also possible without noticeable movements of the filopodia. Here, we demonstrate that polystyrene beads connected by optical tweezers to the ends of adherent filopodia of J774 macrophages, are transported discontinuously toward the cell body. After a typical resting time of 1-2 min, the cargo is moved with alternating velocities, force constants, and friction constants along the surface of the filopodia. This surfing-like behavior along the filopodium is recorded by feedback-controlled interferometric three-dimensional tracking of the bead motions at 10-100 kHz. We measured transport velocities of up to 120 nm/s and transport forces of ∼ 70 pN. Small changes in position, fluctuation width, and temporal correlation, which are invisible in conventional microscopy, indicate molecular reorganization of transport-relevant proteins in different phases of the entire transport process. A detailed analysis implicates a controlled particle transport with fingerprints of a nanoscale unbinding/binding behavior. The manipulation and analysis methods presented in our study may also be helpful in other fields of cellular biophysics.
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Actin-Dependent Regulation of Borrelia burgdorferi Phagocytosis by Macrophages. Curr Top Microbiol Immunol 2016; 399:133-154. [DOI: 10.1007/82_2016_26] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Venter G, Polling S, Pluk H, Venselaar H, Wijers M, Willemse M, Fransen JAM, Wieringa B. Submembranous recruitment of creatine kinase B supports formation of dynamic actin-based protrusions of macrophages and relies on its C-terminal flexible loop. Eur J Cell Biol 2014; 94:114-27. [PMID: 25538032 DOI: 10.1016/j.ejcb.2014.11.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 11/05/2014] [Accepted: 11/06/2014] [Indexed: 12/20/2022] Open
Abstract
Subcellular partitioning of creatine kinase contributes to the formation of patterns in intracellular ATP distribution and the fuelling of cellular processes with a high and sudden energy demand. We have previously shown that brain-type creatine kinase (CK-B) accumulates at the phagocytic cup in macrophages where it is involved in the compartmentalized generation of ATP for actin remodeling. Here, we report that CK-B catalytic activity also helps in the formation of protrusive ruffle structures which are actin-dependent and abundant on the surface of both unstimulated and LPS-activated macrophages. Recruitment of CK-B to these structures occurred transiently and inhibition of the enzyme's catalytic activity with cyclocreatine led to a general smoothening of surface morphology as visualized by scanning electron microscopy. Comparison of the dynamics of distribution of YFP-tagged CK-mutants and isoforms by live imaging revealed that amino acid residues in the C-terminal segment (aa positions 323-330) that forms one of the protein's two mobile loops are involved in partitioning over inner regions of the cytosol and nearby sites where membrane protrusions occur during induction of phagocytic cup formation. Although wt CK-B, muscle-type CK (CK-M), and a catalytically dead CK-B-E232Q mutant with intact loop region were normally recruited from the cytosolic pool, no dynamic transition to the phagocytic cup area was seen for the CK-homologue arginine kinase and a CK-B-D326A mutant protein. Bioinformatics analysis helped us to predict that conformational flexibility of the C-terminal loop, independent of conformational changes induced by substrate binding or catalytic activity, is likely involved in exposing the enzyme for binding at or near the sites of membrane protrusion formation.
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Affiliation(s)
- Gerda Venter
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Saskia Polling
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Helma Pluk
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Hanka Venselaar
- Centre for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Mietske Wijers
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Marieke Willemse
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Jack A M Fransen
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Bé Wieringa
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, PO Box 9101, 6500 HB, Nijmegen, The Netherlands.
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Pauksch L, Rohnke M, Schnettler R, Lips KS. Silver nanoparticles do not alter human osteoclastogenesis but induce cellular uptake. Toxicol Rep 2014; 1:900-908. [PMID: 28962302 PMCID: PMC5598169 DOI: 10.1016/j.toxrep.2014.10.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 09/30/2014] [Accepted: 10/12/2014] [Indexed: 12/20/2022] Open
Abstract
Based on the increasing number of multi-drug resistant bacteria in periprosthetic infections, improvement of the antibacterial activity of commonly used biomaterials must be achieved. The broad-spectrum, high antimicrobial efficacy has made silver nanoparticles a promising new antibacterial agent. However, there is still a serious lack of knowledge concerning the impact of nanosilver on bone cells. For this reason a study was conducted to evaluate the influence of silver nanoparticles on osteoclastogenesis of human peripheral blood mononuclear cells. Upon incubation with subtoxic concentrations of nanosilver the cells did not exhibit changes in osteoclast differentiation and podosomal structures. However, the osteoclasts were able to uptake the nanoparticles, accumulating them in endo-lysosomal compartments. Furthermore, nanosilver exposure led to an increase in oxidative stress and a decrease in clathrin-dependent endocytosis on the mRNA level. In conclusion, our results indicate nanosilver-induced cell stress at higher concentrations. For this reason antibacterial benefits and possible health risks should be weighed in more detail in further studies.
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Affiliation(s)
- Linda Pauksch
- Laboratory for Experimental Trauma Surgery, Justus-Liebig University Giessen, Schubertstrasse 81, 35392 Giessen, Germany
| | - Marcus Rohnke
- Institute for Physical Chemistry, Justus-Liebig University Giessen, Heinrich-Buff-Ring 58, 35392 Giessen, Germany
| | - Reinhard Schnettler
- Laboratory for Experimental Trauma Surgery, Justus-Liebig University Giessen, Schubertstrasse 81, 35392 Giessen, Germany.,Department of Trauma Surgery, University Hospital Giessen and Marburg, Rudolph-Buchheim-Strasse 7, 35392 Giessen, Germany
| | - Katrin S Lips
- Laboratory for Experimental Trauma Surgery, Justus-Liebig University Giessen, Schubertstrasse 81, 35392 Giessen, Germany
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Venter G, Oerlemans FTJJ, Wijers M, Willemse M, Fransen JAM, Wieringa B. Glucose controls morphodynamics of LPS-stimulated macrophages. PLoS One 2014; 9:e96786. [PMID: 24796786 PMCID: PMC4010488 DOI: 10.1371/journal.pone.0096786] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Accepted: 04/11/2014] [Indexed: 12/12/2022] Open
Abstract
Macrophages constantly undergo morphological changes when quiescently surveying the tissue milieu for signs of microbial infection or damage, or after activation when they are phagocytosing cellular debris or foreign material. These morphofunctional alterations require active actin cytoskeleton remodeling and metabolic adaptation. Here we analyzed RAW 264.7 and Maf-DKO macrophages as models to study whether there is a specific association between aspects of carbohydrate metabolism and actin-based processes in LPS-stimulated macrophages. We demonstrate that the capacity to undergo LPS-induced cell shape changes and to phagocytose complement-opsonized zymosan (COZ) particles does not depend on oxidative phosphorylation activity but is fueled by glycolysis. Different macrophage activities like spreading, formation of cell protrusions, as well as phagocytosis of COZ, were thereby strongly reliant on the presence of low levels of extracellular glucose. Since global ATP production was not affected by rewiring of glucose catabolism and inhibition of glycolysis by 2-deoxy-D-glucose and glucose deprivation had differential effects, our observations suggest a non-metabolic role for glucose in actin cytoskeletal remodeling in macrophages, e.g. via posttranslational modification of receptors or signaling molecules, or other effects on the machinery that drives actin cytoskeletal changes. Our findings impute a decisive role for the nutrient state of the tissue microenvironment in macrophage morphodynamics.
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Affiliation(s)
- Gerda Venter
- Department of Cell Biology, Nijmegen Centre for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Frank T. J. J. Oerlemans
- Department of Cell Biology, Nijmegen Centre for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Mietske Wijers
- Department of Cell Biology, Nijmegen Centre for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Marieke Willemse
- Department of Cell Biology, Nijmegen Centre for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Jack A. M. Fransen
- Department of Cell Biology, Nijmegen Centre for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Bé Wieringa
- Department of Cell Biology, Nijmegen Centre for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands
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Hoffmann AK, Naj X, Linder S. Daam1 is a regulator of filopodia formation and phagocytic uptake of Borrelia burgdorferi by primary human macrophages. FASEB J 2014; 28:3075-89. [PMID: 24696301 DOI: 10.1096/fj.13-247049] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Borrelia burgdorferi is the causative agent of Lyme disease, an infectious disease that primarily affects the skin, nervous system, and joints. Uptake of borreliae by immune cells is decisive for the course of the infection, and remodelling of the host actin cytoskeleton is crucial in this process. In this study, we showed that the actin-regulatory formin Daam1 is important in Borrelia phagocytosis by primary human macrophages. Uptake of borreliae proceeds preferentially through capture by filopodia and formation of coiling pseudopods that enwrap the spirochetes. Using immunofluorescence, we localized endogenous and overexpressed Daam1 to filopodia and to F-actin-rich uptake structures. Live-cell imaging further showed that Daam1 is enriched at coiling pseudopods that arise from the macrophage surface. This filopodia-independent step was corroborated by control experiments of phagocytic cup formation with latex beads. Moreover, siRNA-mediated knockdown of Daam1 led to a 65% reduction of borreliae-induced filopodia, and, as shown by the outside-inside staining technique, to a 50% decrease in phagocytic uptake of borreliae, as well as a 37% reduction in coiling pseudopod formation. Collectively, we showed that Daam1 plays a dual role in the phagocytic uptake of borreliae: first, as a regulator of filopodia, which are used for capturing spirochetes, and second, in the formation of the coiling pseudopod that enwraps the bacterial cell. These data identify Daam1 as a novel regulator of B. burgdorferi phagocytosis. At the same time, this is the first demonstration of a role for Daam1 in phagocytic processes in general.-Hoffmann, A.-K., Naj, X., Linder, S. Daam1 is a regulator of filopodia formation and phagocytic uptake of Borrelia burgdorferi by primary human macrophages.
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Affiliation(s)
- Ann-Kathrin Hoffmann
- Institute for Medical Microbiology, Virology, and Hygiene, University Medical Center Eppendorf, Hamburg, Germany
| | - Xenia Naj
- Institute for Medical Microbiology, Virology, and Hygiene, University Medical Center Eppendorf, Hamburg, Germany
| | - Stefan Linder
- Institute for Medical Microbiology, Virology, and Hygiene, University Medical Center Eppendorf, Hamburg, Germany
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Blanchoin L, Boujemaa-Paterski R, Sykes C, Plastino J. Actin dynamics, architecture, and mechanics in cell motility. Physiol Rev 2014; 94:235-63. [PMID: 24382887 DOI: 10.1152/physrev.00018.2013] [Citation(s) in RCA: 845] [Impact Index Per Article: 84.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Tight coupling between biochemical and mechanical properties of the actin cytoskeleton drives a large range of cellular processes including polarity establishment, morphogenesis, and motility. This is possible because actin filaments are semi-flexible polymers that, in conjunction with the molecular motor myosin, can act as biological active springs or "dashpots" (in laymen's terms, shock absorbers or fluidizers) able to exert or resist against force in a cellular environment. To modulate their mechanical properties, actin filaments can organize into a variety of architectures generating a diversity of cellular organizations including branched or crosslinked networks in the lamellipodium, parallel bundles in filopodia, and antiparallel structures in contractile fibers. In this review we describe the feedback loop between biochemical and mechanical properties of actin organization at the molecular level in vitro, then we integrate this knowledge into our current understanding of cellular actin organization and its physiological roles.
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Filopodial retraction force is generated by cortical actin dynamics and controlled by reversible tethering at the tip. Proc Natl Acad Sci U S A 2013; 110:18928-33. [PMID: 24198333 DOI: 10.1073/pnas.1316572110] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Filopodia are dynamic, finger-like plasma membrane protrusions that sense the mechanical and chemical surroundings of the cell. Here, we show in epithelial cells that the dynamics of filopodial extension and retraction are determined by the difference between the actin polymerization rate at the tip and the retrograde flow at the base of the filopodium. Adhesion of a bead to the filopodial tip locally reduces actin polymerization and leads to retraction via retrograde flow, reminiscent of a process used by pathogens to invade cells. Using optical tweezers, we show that filopodial retraction occurs at a constant speed against counteracting forces up to 50 pN. Our measurements point toward retrograde flow in the cortex together with frictional coupling between the filopodial and cortical actin networks as the main retraction-force generator for filopodia. The force exerted by filopodial retraction, however, is limited by the connection between filopodial actin filaments and the membrane at the tip. Upon mechanical rupture of the tip connection, filopodia exert a passive retraction force of 15 pN via their plasma membrane. Transient reconnection at the tip allows filopodia to continuously probe their surroundings in a load-and-fail manner within a well-defined force range.
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Tumor stiffness is unrelated to myosin light chain phosphorylation in cancer cells. PLoS One 2013; 8:e79776. [PMID: 24224004 PMCID: PMC3817105 DOI: 10.1371/journal.pone.0079776] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Accepted: 09/25/2013] [Indexed: 01/15/2023] Open
Abstract
Many tumors are stiffer than their surrounding tissue. This increase in stiffness has been attributed, in part, to a Rho-dependent elevation of myosin II light chain phosphorylation. To characterize this mechanism further, we studied myosin light chain kinase (MLCK), the main enzyme that phosphorylates myosin II light chains. We anticipated that increases in MLCK expression and activity would contribute to the increased stiffness of cancer cells. However, we find that MLCK mRNA and protein levels are substantially less in cancer cells and tissues than in normal cells. Consistent with this observation, cancer cells contract 3D collagen matrices much more slowly than normal cells. Interestingly, inhibiting MLCK or Rho kinase did not affect the 3D gel contractions while blebbistatin partially and cytochalasin D maximally inhibited contractions. Live cell imaging of cells in collagen gels showed that cytochalasin D inhibited filopodia-like projections that formed between cells while a MLCK inhibitor had no effect on these projections. These data suggest that myosin II phosphorylation is dispensable in regulating the mechanical properties of tumors.
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Möller J, Lühmann T, Chabria M, Hall H, Vogel V. Macrophages lift off surface-bound bacteria using a filopodium-lamellipodium hook-and-shovel mechanism. Sci Rep 2013; 3:2884. [PMID: 24097079 PMCID: PMC3791455 DOI: 10.1038/srep02884] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Accepted: 09/18/2013] [Indexed: 01/06/2023] Open
Abstract
To clear pathogens from host tissues or biomaterial surfaces, phagocytes have to break the adhesive bacteria-substrate interactions. Here we analysed the mechanobiological process that enables macrophages to lift-off and phagocytose surface-bound Escherichia coli (E. coli). In this opsonin-independent process, macrophage filopodia hold on to the E. coli fimbriae long enough to induce a local protrusion of a lamellipodium. Specific contacts between the macrophage and E. coli are formed via the glycoprotein CD48 on filopodia and the adhesin FimH on type 1 fimbriae (hook). We show that bacterial detachment from surfaces occurrs after a lamellipodium has protruded underneath the bacterium (shovel), thereby breaking the multiple bacterium-surface interactions. After lift-off, the bacterium is engulfed by a phagocytic cup. Force activated catch bonds enable the long-term survival of the filopodium-fimbrium interactions while soluble mannose inhibitors and CD48 antibodies suppress the contact formation and thereby inhibit subsequent E. coli phagocytosis.
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Affiliation(s)
- Jens Möller
- Laboratory of Applied Mechanobiology, Department of Health Sciences and Technology, ETH Zurich, CH-8093 Zurich, Switzerland
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Bornschlögl T. How filopodia pull: what we know about the mechanics and dynamics of filopodia. Cytoskeleton (Hoboken) 2013; 70:590-603. [PMID: 23959922 DOI: 10.1002/cm.21130] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 07/31/2013] [Accepted: 08/01/2013] [Indexed: 01/04/2023]
Abstract
In recent years, the dynamic, hair-like cell protrusions called filopodia have attracted considerable attention. They have been found in a multitude of different cell types and are often called "sensory organelles," since they seem to sense the mechanical and chemical environment of a cell. Once formed, filopodia can exhibit complex behavior, they can grow and retract, push or pull, and transform into distinct structures. They are often found to make first adhesive contact with the extracellular matrix, pathogens or with adjacent cells, and to subsequently exert pulling forces. Much is known about the cytoskeletal players involved in filopodia formation, but only recently have we started to explore the mechanics of filopodia together with the related cytoskeletal dynamics. This review summarizes current advancements in our understanding of the mechanics and dynamics of filopodia, with a focus on the molecular mechanisms behind filopodial force exertion.
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Affiliation(s)
- Thomas Bornschlögl
- Institut Curie, Laboratoire, Physico-Chimie UMR CNRS, 168, 11 Rue Pierre et Marie Curie, 75005, Paris, France
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Adenosine-A3 receptors in neutrophil microdomains promote the formation of bacteria-tethering cytonemes. EMBO Rep 2013; 14:726-32. [PMID: 23817552 PMCID: PMC3736131 DOI: 10.1038/embor.2013.89] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Revised: 06/04/2013] [Accepted: 06/06/2013] [Indexed: 01/09/2023] Open
Abstract
These study shows that A3ARs aggregate in polarized immunomodulatory microdomains on human neutrophils and induce filipodia-like projections that tether and 'reel-in' pathogens, increasing phagocytic efficiency. The A3-adenosine receptor (A3AR) has recently emerged as a key regulator of neutrophil behaviour. Using a fluorescent A3AR ligand, we show that A3ARs aggregate in highly polarized immunomodulatory microdomains on human neutrophil membranes. In addition to regulating chemotaxis, A3ARs promote the formation of filipodia-like projections (cytonemes) that can extend up to 100 μm to tether and ‘reel in' pathogens. Exposure to bacteria or an A3AR agonist stimulates the formation of these projections and bacterial phagocytosis, whereas an A3AR-selective antagonist inhibits cytoneme formation. Our results shed new light on the behaviour of neutrophils and identify the A3AR as a potential target for modulating their function.
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Irmscher M, de Jong AM, Kress H, Prins MWJ. A method for time-resolved measurements of the mechanics of phagocytic cups. J R Soc Interface 2013; 10:20121048. [PMID: 23466558 DOI: 10.1098/rsif.2012.1048] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The internalization of matter by phagocytosis is of key importance in the defence against bacterial pathogens and in the control of cancerous tumour growth. Despite the fact that phagocytosis is an inherently mechanical process, little is known about the forces and energies that a cell requires for internalization. Here, we use functionalized magnetic particles as phagocytic targets and track their motion while actuating them in an oscillating magnetic field, in order to measure the translational and rotational stiffnesses of the phagocytic cup as a function of time. The measured evolution of stiffness reveals a characteristic pattern with a pronounced peak preceding the finalization of uptake. The measured stiffness values and their time dependence can be interpreted with a model that describes the phagocytic cup as a prestressed membrane connected to an elastically deformable actin cortex. In the context of this model, the stiffness peak is a direct manifestation of a previously described mechanical bottleneck, and a comparison of model and data suggests that the membrane advances around the particle at a speed of about 20 nm s(-1). This approach is a novel way of measuring the progression of emerging phagocytic cups and their mechanical properties in situ and in real time.
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Affiliation(s)
- Matthias Irmscher
- Department of Applied Physics, Eindhoven University of Technology, Eindhoven, The Netherlands
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Patel NR, Bole M, Chen C, Hardin CC, Kho AT, Mih J, Deng L, Butler J, Tschumperlin D, Fredberg JJ, Krishnan R, Koziel H. Cell elasticity determines macrophage function. PLoS One 2012; 7:e41024. [PMID: 23028423 PMCID: PMC3445606 DOI: 10.1371/journal.pone.0041024] [Citation(s) in RCA: 195] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Accepted: 06/16/2012] [Indexed: 12/11/2022] Open
Abstract
Macrophages serve to maintain organ homeostasis in response to challenges from injury, inflammation, malignancy, particulate exposure, or infection. Until now, receptor ligation has been understood as being the central mechanism that regulates macrophage function. Using macrophages of different origins and species, we report that macrophage elasticity is a major determinant of innate macrophage function. Macrophage elasticity is modulated not only by classical biologic activators such as LPS and IFN-γ, but to an equal extent by substrate rigidity and substrate stretch. Macrophage elasticity is dependent upon actin polymerization and small rhoGTPase activation, but functional effects of elasticity are not predicted by examination of gene expression profiles alone. Taken together, these data demonstrate an unanticipated role for cell elasticity as a common pathway by which mechanical and biologic factors determine macrophage function.
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Affiliation(s)
- Naimish R Patel
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America.
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Romero S, Quatela A, Bornschlögl T, Bornschlög T, Guadagnini S, Bassereau P, Tran Van Nhieu G. Filopodium retraction is controlled by adhesion to its tip. J Cell Sci 2012; 125:4999-5004. [PMID: 22899718 DOI: 10.1242/jcs.104778] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Filopodia are thin cell extensions sensing the environment. They play an essential role during cell migration, cell-cell or cell-matrix adhesion, by initiating contacts and conveying signals to the cell cortex. Pathogenic microorganisms can hijack filopodia to invade cells by inducing their retraction towards the cell body. Because their dynamics depend on a discrete number of actin filaments, filopodia provide a model of choice to study elementary events linked to adhesion and downstream signalling. However, the determinants controlling filopodial sensing are not well characterized. In this study, we used beads functionalized with different ligands that triggered filopodial retraction when in contact with filopodia of epithelial cells. With optical tweezers, we were able to measure forces stalling the retraction of a single filopodium. We found that the filopodial stall force depends on the coating of the bead. Stall forces reached 8 pN for beads coated with the β1 integrin ligand Yersinia Invasin, whereas retraction was stopped with a higher force of 15 pN when beads were functionalized with carboxyl groups. In all cases, stall forces increased in relation to the density of ligands contacting filopodial tips and were independent of the optical trap stiffness. Unexpectedly, a discrete and small number of Shigella type three secretion systems induced stall forces of 10 pN. These results suggest that the number of receptor-ligand interactions at the filopodial tip determines the maximal retraction force exerted by filopodia but a discrete number of clustered receptors is sufficient to induce high retraction stall forces.
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Affiliation(s)
- Stephane Romero
- Equipe Communication Intercellulaire et Infections Microbiennes, Centre de Recherche Interdisciplinaire en Biologie (CIRB), Collège de France, Paris, France
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Möller J, Luehmann T, Hall H, Vogel V. The race to the pole: how high-aspect ratio shape and heterogeneous environments limit phagocytosis of filamentous Escherichia coli bacteria by macrophages. NANO LETTERS 2012; 12:2901-2905. [PMID: 22591454 DOI: 10.1021/nl3004896] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
While bioengineers ask how the shape of diagnostic and therapeutic particles impacts their pharmacological efficiency, biodistribution, and toxicity, microbiologists suggested that morphological adaptations enable pathogens to perhaps evade the immune response. Here, a shape-dependent process is described that limits phagocytosis of filamentous Escherichia coli bacteria by macrophages: successful uptake requires access to one of the terminal bacterial filament poles. By exploiting micropatterned surfaces, we further demonstrate that microenvironmental heterogeneities can slow or inhibit phagocytosis. A comparison to existing literature reveals a common shape-controlled uptake mechanism for both high-aspect ratio filamentous bacteria and engineered particles.
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Affiliation(s)
- Jens Möller
- Laboratory for Biologically Oriented Materials, Department of Health Sciences and Technology, ETH Zurich, CH-8093 Zurich, Switzerland
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Mechanism of Male Gamete Motility in Araphid Pennate Diatoms from the Genus Tabularia (Bacillariophyta). Protist 2012; 163:480-94. [DOI: 10.1016/j.protis.2011.09.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Revised: 09/09/2011] [Accepted: 09/21/2011] [Indexed: 11/18/2022]
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Romero S, Grompone G, Carayol N, Mounier J, Guadagnini S, Prevost MC, Sansonetti PJ, Van Nhieu GT. ATP-mediated Erk1/2 activation stimulates bacterial capture by filopodia, which precedes Shigella invasion of epithelial cells. Cell Host Microbe 2011; 9:508-19. [PMID: 21669399 DOI: 10.1016/j.chom.2011.05.005] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Revised: 04/19/2011] [Accepted: 05/23/2011] [Indexed: 11/29/2022]
Abstract
Shigella, the causative agent of bacillary dysentery in humans, invades epithelial cells, using a type III secretory system (T3SS) to inject bacterial effectors into host cells and remodel the actin cytoskeleton. ATP released through connexin hemichanels on the epithelial membrane stimulates Shigella invasion and dissemination in epithelial cells. Here, we show that prior to contact with the cell body, Shigella is captured by nanometer-thin micropodial extensions (NMEs) at a distance from the cell surface, in a process involving the T3SS tip complex proteins and stimulated by ATP- and connexin-mediated signaling. Upon bacterial contact, NMEs retract, bringing bacteria in contact with the cell body, where invasion occurs. ATP stimulates Erk1/2 activation, which controls actin retrograde flow in NMEs and their retraction. These findings reveal previously unappreciated facets of interaction of an invasive bacterium with host cells and a prominent role for Erk1/2 in the control of filopodial dynamics.
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Affiliation(s)
- Stéphane Romero
- Equipe Communication Intercellulaire et Infections Microbiennes, Centre de Recherche Interdisciplinaire en Biologie, Collège de France, 75005 Paris, France
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Human immunodeficiency virus type 1 endocytic trafficking through macrophage bridging conduits facilitates spread of infection. J Neuroimmune Pharmacol 2011; 6:658-75. [PMID: 21789505 PMCID: PMC3232570 DOI: 10.1007/s11481-011-9298-z] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Accepted: 07/10/2011] [Indexed: 11/26/2022]
Abstract
Bridging conduits (BC) sustain communication and homeostasis between distant tethered cells. These are also exploited commonly for direct cell-to-cell transfer of microbial agents. Conduits efficiently spread infection, effectively, at speeds faster than fluid phase exchange while shielding the microbe against otherwise effective humoral immunity. Our laboratory has sought to uncover the mechanism(s) for these events for human immunodeficiency virus type one (HIV-1) infection. Indeed, in our prior works HIV-1 Env and Gag antigen and fluorescent virus tracking were shown sequestered into endoplasmic reticulum-Golgi organelles but the outcomes for spreading viral infection remained poorly defined. Herein, we show that HIV-1 specifically traffics through endocytic compartments contained within BC and directing such macrophage-to-macrophage viral transfers. Following clathrin-dependent viral entry, HIV-1 constituents bypass degradation by differential sorting from early to Rab11+ recycling endosomes and multivesicular bodies. Virus-containing endocytic viral cargoes propelled by myosin II through BC spread to neighboring uninfected cells. Disruption of endosomal motility with cytochalasin D, nocodasole and blebbistatin diminish intercellular viral spread. These data lead us to propose that HIV-1 hijacks macrophage endocytic and cytoskeletal machineries for high-speed cell-to-cell spread.
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Zidovska A, Sackmann E. On the mechanical stabilization of filopodia. Biophys J 2011; 100:1428-37. [PMID: 21402024 DOI: 10.1016/j.bpj.2011.01.069] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Revised: 01/12/2011] [Accepted: 01/27/2011] [Indexed: 01/13/2023] Open
Abstract
We studied force-induced elongation of filopodia by coupling magnetic tweezers to the tip through the bacterial coat protein invasin, which couples the force generator to the actin bundles (through myosin X), thus impeding the growth of the actin plus end. Single force pulses (15-30 s) with amplitudes between 20 and 600 pN and staircase-like force scenarios (amplitudes, ∼50 pN; step widths, 30 s) were applied. In both cases, the responses consist of a fast viscoelastic deflection followed by a linear flow regime. The deflections are reversible after switching off the forces, suggesting a mechanical memory. The elongation velocity exhibits an exponential distribution (half-width <v(1/2)>, ∼0.02 μm s(-1)) and did not increase systematically with the force amplitudes. We estimate the bending modulus (0.4 × 10(-23) J m) and the number of actin filaments (∼10) by analyzing filopodium bending fluctuations. Sequestering of intracellular Ca(2+) by BAPTA caused a strong reduction in the amplitude of elongation, whereas latrunculin A resulted in loss of the elastic response. We attribute the force-independent velocity to the elongation of actin bundles enabled by the force-induced actin membrane uncoupling and the reversibility by the treadmilling mechanism and an elastic response.
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