1
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Jahnke K, Pavlovic M, Xu W, Chen A, Knowles TPJ, Arriaga LR, Weitz DA. Polysaccharide functionalization reduces lipid vesicle stiffness. Proc Natl Acad Sci U S A 2024; 121:e2317227121. [PMID: 38771870 PMCID: PMC11145274 DOI: 10.1073/pnas.2317227121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 04/15/2024] [Indexed: 05/23/2024] Open
Abstract
The biophysical properties of lipid vesicles are important for their stability and integrity, key parameters that control the performance when these vesicles are used for drug delivery. The vesicle properties are determined by the composition of lipids used to form the vesicle. However, for a given lipid composition, they can also be tailored by tethering polymers to the membrane. Typically, synthetic polymers like polyethyleneglycol are used to increase vesicle stability, but the use of polysaccharides in this context is much less explored. Here, we report a general method for functionalizing lipid vesicles with polysaccharides by binding them to cholesterol. We incorporate the polysaccharides on the outer membrane leaflet of giant unilamellar vesicles (GUVs) and investigate their effect on membrane mechanics using micropipette aspiration. We find that the presence of the glycolipid functionalization produces an unexpected softening of GUVs with fluid-like membranes. By contrast, the functionalization of GUVs with polyethylene glycol does not reduce their stretching modulus. This work provides the potential means to study membrane-bound meshworks of polysaccharides similar to the cellular glycocalyx; moreover, it can be used for tuning the mechanical properties of drug delivery vehicles.
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Affiliation(s)
- Kevin Jahnke
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA02138
| | - Marko Pavlovic
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA02138
| | - Wentao Xu
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA02138
| | - Anqi Chen
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA02138
| | - Tuomas P. J. Knowles
- Yusuf Hamied Department of Chemistry, University of Cambridge, CambridgeCB2 1EW, United Kingdom
| | - Laura R. Arriaga
- Department of Theoretical Condensed Matter Physics, Condensed Matter Physics Center and Instituto Nicolás Cabrera, Universidad Autónoma de Madrid, Madrid28049, Spain
| | - David A. Weitz
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA02138
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA02115
- Department of Physics, Harvard University, Cambridge, MA02138
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2
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Wang Y, Wang Y, Li X, Gao Y, Pan X, Lü J. Protopanaxadiol Targeting Membrane Induces HepG2 Cell Apoptosis Via Raft-like Formation and Tubulation Disruption. Cell Biochem Biophys 2024:10.1007/s12013-024-01270-4. [PMID: 38613700 DOI: 10.1007/s12013-024-01270-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/03/2024] [Indexed: 04/15/2024]
Abstract
Protopanaxadiol (PPD), which has a molecular structure similar to cholesterol, is a potent anticancer agent that has been proposed to target the lipid membrane for the pharmacological effects. However, the underlying mechanism by which PPD modulates the cell membrane leading to cancer cell death is not be fully understood. In this work, we used single cell infrared spectroscopy, scanning electron microscopy and confocal microscopy to investigate the effects of PPD on human hepatocellular carcinoma (HepG2) cells, focusing on the change in membrane structure. We found that PPD significantly reduced the number of membrane tubules over the course of treatment. Interestingly, the addition of PPD could promote the formation of lipid raft-like domains (PPD rafts) and even restore the domain disruption caused by methyl-beta-cyclodextrin depletion of membrane cholesterol. In addition, PPD pre-treatment may increase the induction effect of FasL, which impairs cell viability, although it does not appear to be beneficial for Fas clustering in the PPD rafts. Collectively, these results highlight a non-classical mechanism by which PPD induces HepG2 apoptosis by directly affecting the physical properties of the cell membrane, providing a novel insight into understanding membrane-targeted therapy.
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Affiliation(s)
- Yue Wang
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201203, China
- College of Pharmacy, Binzhou Medical University, Yantai, 264003, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yadi Wang
- College of Pharmacy, Binzhou Medical University, Yantai, 264003, China
| | - Xueling Li
- Shanghai University of Medicine and Health Sciences, Shanghai, 201318, China
| | - Yu Gao
- College of Pharmacy, Binzhou Medical University, Yantai, 264003, China
| | - Xiaohong Pan
- College of Pharmacy, Binzhou Medical University, Yantai, 264003, China.
| | - Junhong Lü
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201203, China.
- College of Pharmacy, Binzhou Medical University, Yantai, 264003, China.
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3
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Dey M, Sharma A, Dhanawat G, Gupta D, Harshan KH, Parveen N. Synergistic Binding of SARS-CoV-2 to ACE2 and Gangliosides in Native Lipid Membranes. ACS Infect Dis 2024; 10:907-916. [PMID: 38412250 DOI: 10.1021/acsinfecdis.3c00519] [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: 02/29/2024]
Abstract
Viruses utilize cell surface glycans and plasma membrane receptors to attain an adequate attachment strength for initiating cellular entry. We show that SARS-CoV-2 particles bind to endogenous ACE2 receptors and added sialylated gangliosides in near-native membranes. This was explored using supported membrane bilayers (SMBs) that were formed using plasma membrane vesicles having endogenous ACE2 and GD1a gangliosides reconstituted in lipid vesicles. The virus binding rate to the SMBs is influenced by GD1a and inhibition of the ganglioside reduces the extent of virus binding to the membrane receptors. Using combinations of inhibition assays, we confirm that added GD1a in lipid membranes increases the availability of the endogenous ACE2 receptor and results in the synergistic binding of SARS-CoV-2 to the membrane receptors in SMBs.
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Affiliation(s)
- Manorama Dey
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Anurag Sharma
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Garvita Dhanawat
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Divya Gupta
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad 500007, India
| | - Krishnan H Harshan
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad 500007, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Nagma Parveen
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
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4
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Pokorny L, Burden JJ, Albrecht D, Bamford R, Leigh KE, Sridhar P, Knowles TJ, Modis Y, Mercer J. The vaccinia chondroitin sulfate binding protein drives host membrane curvature to facilitate fusion. EMBO Rep 2024; 25:1310-1325. [PMID: 38321165 PMCID: PMC10933376 DOI: 10.1038/s44319-023-00040-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 12/12/2023] [Accepted: 12/13/2023] [Indexed: 02/08/2024] Open
Abstract
Cellular attachment of viruses determines their cell tropism and species specificity. For entry, vaccinia, the prototypic poxvirus, relies on four binding proteins and an eleven-protein entry fusion complex. The contribution of the individual virus binding proteins to virion binding orientation and membrane fusion is unclear. Here, we show that virus binding proteins guide side-on virion binding and promote curvature of the host membrane towards the virus fusion machinery to facilitate fusion. Using a membrane-bleb model system together with super-resolution and electron microscopy we find that side-bound vaccinia virions induce membrane invagination in the presence of low pH. Repression or deletion of individual binding proteins reveals that three of four contribute to binding orientation, amongst which the chondroitin sulfate binding protein, D8, is required for host membrane bending. Consistent with low-pH dependent macropinocytic entry of vaccinia, loss of D8 prevents virion-associated macropinosome membrane bending, disrupts fusion pore formation and infection. Our results show that viral binding proteins are active participants in successful virus membrane fusion and illustrate the importance of virus protein architecture for successful infection.
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Affiliation(s)
- Laura Pokorny
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK
- MRC-LMCB, University College London, London, WC1E 6BT, UK
| | - Jemima J Burden
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - David Albrecht
- MRC-LMCB, University College London, London, WC1E 6BT, UK
| | - Rebecca Bamford
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK
- MRC-LMCB, University College London, London, WC1E 6BT, UK
| | - Kendra E Leigh
- Molecular Immunity Unit, Department of Medicine, University of Cambridge, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, CB2 0QH, UK
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), University of Cambridge School of Clinical Medicine, Cambridge, CB2 0AW, UK
| | - Pooja Sridhar
- School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Timothy J Knowles
- School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Yorgo Modis
- Molecular Immunity Unit, Department of Medicine, University of Cambridge, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, CB2 0QH, UK
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), University of Cambridge School of Clinical Medicine, Cambridge, CB2 0AW, UK
| | - Jason Mercer
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK.
- MRC-LMCB, University College London, London, WC1E 6BT, UK.
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5
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Li Y, Wang H, Chen Y, Ding L, Ju H. In Situ Glycan Analysis and Editing in Living Systems. JACS AU 2024; 4:384-401. [PMID: 38425935 PMCID: PMC10900212 DOI: 10.1021/jacsau.3c00717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 12/15/2023] [Accepted: 12/19/2023] [Indexed: 03/02/2024]
Abstract
Besides proteins and nucleic acids, carbohydrates are also ubiquitous building blocks of living systems. Approximately 70% of mammalian proteins are glycosylated. Glycans not only provide structural support for living systems but also act as crucial regulators of cellular functions. As a result, they are considered essential pieces of the life science puzzle. However, research on glycans has lagged far behind that on proteins and nucleic acids. The main reason is that glycans are not direct products of gene coding, and their synthesis is nontemplated. In addition, the diversity of monosaccharide species and their linkage patterns contribute to the complexity of the glycan structures, which is the molecular basis for their diverse functions. Research in glycobiology is extremely challenging, especially for the in situ elucidation of glycan structures and functions. There is an urgent need to develop highly specific glycan labeling tools and imaging methods and devise glycan editing strategies. This Perspective focuses on the challenges of in situ analysis of glycans in living systems at three spatial levels (i.e., cell, tissue, and in vivo) and highlights recent advances and directions in glycan labeling, imaging, and editing tools. We believe that examining the current development landscape and the existing bottlenecks can drive the evolution of in situ glycan analysis and intervention strategies and provide glycan-based insights for clinical diagnosis and therapeutics.
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Affiliation(s)
- Yiran Li
- State
Key Laboratory of Analytical Chemistry for Life Science, School of
Chemistry and Chemical Engineering, Nanjing
University, Nanjing 210023, China
| | - Haiqi Wang
- State
Key Laboratory of Analytical Chemistry for Life Science, School of
Chemistry and Chemical Engineering, Nanjing
University, Nanjing 210023, China
| | - Yunlong Chen
- State
Key Laboratory of Analytical Chemistry for Life Science, School of
Chemistry and Chemical Engineering, Nanjing
University, Nanjing 210023, China
| | - Lin Ding
- State
Key Laboratory of Analytical Chemistry for Life Science, School of
Chemistry and Chemical Engineering, Nanjing
University, Nanjing 210023, China
- Chemistry
and Biomedicine Innovation Center (ChemBIC), Nanjing University, Nanjing 210023, China
| | - Huangxian Ju
- State
Key Laboratory of Analytical Chemistry for Life Science, School of
Chemistry and Chemical Engineering, Nanjing
University, Nanjing 210023, China
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6
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Xiong Y, Libby KA, Su X. The physical landscape of CAR-T synapse. Biophys J 2023:S0006-3495(23)00581-7. [PMID: 37715447 DOI: 10.1016/j.bpj.2023.09.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 08/30/2023] [Accepted: 09/12/2023] [Indexed: 09/17/2023] Open
Abstract
Chimeric antigen receptor (CAR)-T cells form dynamic immunological synapses with their cancer cell targets. After a CAR-antigen engagement, the CAR-T synapse forms, matures, and finally disassembles, accompanied by substantial remodeling of cell surface proteins, lipids, and glycans. In this review, we provide perspectives for understanding protein distribution, membrane topology, and force transmission across the CAR-T synapse. We highlight the features of CAR-T synapses that differ from T cell receptor synapses, including the disorganized protein pattern, adjustable synapse width, diverse mechano-responding properties, and resulting signaling consequences. Through a range of examples, we illustrate how revealing the biophysical nature of the CAR-T synapse could guide the design of CAR-Ts with improved anti-tumor function.
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Affiliation(s)
- Yiwei Xiong
- Department of Cell Biology, Yale School of Medicine, New Haven, Connecticut
| | - Kendra A Libby
- Department of Cell Biology, Yale School of Medicine, New Haven, Connecticut; Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts; Ragon Institute of MGH, MIT and Harvard, Cambridge, Massachusetts
| | - Xiaolei Su
- Department of Cell Biology, Yale School of Medicine, New Haven, Connecticut; Yale Cancer Center, Yale University, New Haven, Connecticut; Yale Stem Cell Center, Yale University, New Haven, Connecticut.
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7
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Arnold DP, Takatori SC. Bio-enabled Engineering of Multifunctional "Living" Surfaces. ACS NANO 2023. [PMID: 37294942 DOI: 10.1021/acsnano.3c03138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Through the magic of "active matter"─matter that converts chemical energy into mechanical work to drive emergent properties─biology solves a myriad of seemingly enormous physical challenges. Using active matter surfaces, for example, our lungs clear an astronomically large number of particulate contaminants that accompany each of the 10,000 L of air we respire per day, thus ensuring that the lungs' gas exchange surfaces remain functional. In this Perspective, we describe our efforts to engineer artificial active surfaces that mimic active matter surfaces in biology. Specifically, we seek to assemble the basic active matter components─mechanical motor, driven constituent, and energy source─to design surfaces that support the continuous operation of molecular sensing, recognition, and exchange. The successful realization of this technology would generate multifunctional, "living" surfaces that combine the dynamic programmability of active matter and the molecular specificity of biological surfaces and apply them to applications in biosensors, chemical diagnostics, and other surface transport and catalytic processes. We describe our recent efforts in bio-enabled engineering of living surfaces through the design of molecular probes to understand and integrate native biological membranes into synthetic materials.
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Affiliation(s)
- Daniel P Arnold
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
| | - Sho C Takatori
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
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8
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Arnold DP, Xu Y, Takatori SC. Antibody binding reports spatial heterogeneities in cell membrane organization. Nat Commun 2023; 14:2884. [PMID: 37208326 DOI: 10.1038/s41467-023-38525-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 05/05/2023] [Indexed: 05/21/2023] Open
Abstract
The spatial organization of cell membrane glycoproteins and glycolipids is critical for mediating the binding of ligands, receptors, and macromolecules on the plasma membrane. However, we currently do not have the methods to quantify the spatial heterogeneities of macromolecular crowding on live cell surfaces. In this work, we combine experiment and simulation to report crowding heterogeneities on reconstituted membranes and live cell membranes with nanometer spatial resolution. By quantifying the effective binding affinity of IgG monoclonal antibodies to engineered antigen sensors, we discover sharp gradients in crowding within a few nanometers of the crowded membrane surface. Our measurements on human cancer cells support the hypothesis that raft-like membrane domains exclude bulky membrane proteins and glycoproteins. Our facile and high-throughput method to quantify spatial crowding heterogeneities on live cell membranes may facilitate monoclonal antibody design and provide a mechanistic understanding of plasma membrane biophysical organization.
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Affiliation(s)
- Daniel P Arnold
- Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Yaxin Xu
- Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Sho C Takatori
- Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA.
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9
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Nicolson GL, Ferreira de Mattos G. The Fluid-Mosaic model of cell membranes: A brief introduction, historical features, some general principles, and its adaptation to current information. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2023; 1865:184135. [PMID: 36746313 DOI: 10.1016/j.bbamem.2023.184135] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 01/27/2023] [Accepted: 01/30/2023] [Indexed: 02/07/2023]
Abstract
The Fluid-Mosaic Membrane (FMM) model was originally proposed as a general, nanometer-scale representation of cell membranes (Singer and Nicolson, 1972). The FMM model was based on some general principles, such as thermodynamic considerations, intercalation of globular proteins into a lipid bilayer, independent protein and lipid dynamics, cooperativity and other characteristics. Other models had trimolecular structures or membrane globular lipoprotein units. These latter models were flawed, because they did not allow autonomous lipids, membrane domains or discrete lateral dynamics. The FMM model was also consistent with membrane asymmetry, cis- and trans-membrane linkages and associations of membrane components into multi-molecular complexes and domains. It has remained useful for explaining the basic organizational principles and properties of various biological membranes. New information has been added, such as membrane-associated cytoskeletal assemblies, extracellular matrix interactions, transmembrane controls, specialized lipid-protein domains that differ in compositions, rotational and lateral mobilities, lifetimes, functions, and other characteristics. The presence of dense, structured membrane domains has reduced significantly the extent of fluid-lipid membrane areas, and the FMM model is now considered to be more mosaic and dense than the original proposal.
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Affiliation(s)
- Garth L Nicolson
- Department of Molecular Pathology, The Institute for Molecular Medicine, Huntington Beach, CA 92647, USA.
| | - Gonzalo Ferreira de Mattos
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Department of Biophysics, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
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10
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Purushothaman A, Mohajeri M, Lele TP. The role of glycans in the mechanobiology of cancer. J Biol Chem 2023; 299:102935. [PMID: 36693448 PMCID: PMC9930169 DOI: 10.1016/j.jbc.2023.102935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 01/04/2023] [Accepted: 01/05/2023] [Indexed: 01/22/2023] Open
Abstract
Although cancer is a genetic disease, physical changes such as stiffening of the extracellular matrix also commonly occur in cancer. Cancer cells sense and respond to extracellular matrix stiffening through the process of mechanotransduction. Cancer cell mechanotransduction can enhance cancer-promoting cell behaviors such as survival signaling, proliferation, and migration. Glycans, carbohydrate-based polymers, have recently emerged as important mediators and/or modulators of cancer cell mechanotransduction. Stiffer tumors are characterized by increased glycan content on cancer cells and their associated extracellular matrix. Here we review the role of cancer-associated glycans in coupled mechanical and biochemical alterations during cancer progression. We discuss the recent evidence on how increased expression of different glycans, in the form of glycoproteins and proteoglycans, contributes to both mechanical changes in tumors and corresponding cancer cell responses. We conclude with a summary of emerging tools that can be used to modify glycans for future studies in cancer mechanobiology.
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Affiliation(s)
- Anurag Purushothaman
- Department of Biomedical Engineering, Texas A&M University, Houston, Texas, USA.
| | - Mohammad Mohajeri
- Department of Biomedical Engineering, Texas A&M University, College Station, Texas, USA
| | - Tanmay P Lele
- Department of Biomedical Engineering, Texas A&M University, Houston, Texas, USA; Department of Biomedical Engineering, Texas A&M University, College Station, Texas, USA; Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, Texas, USA; Department of Translational Medical Sciences, Texas A&M University, Houston, Texas, USA.
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11
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Kozlov MM, Taraska JW. Generation of nanoscopic membrane curvature for membrane trafficking. Nat Rev Mol Cell Biol 2023; 24:63-78. [PMID: 35918535 DOI: 10.1038/s41580-022-00511-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/20/2022] [Indexed: 11/09/2022]
Abstract
Curved membranes are key features of intracellular organelles, and their generation involves dynamic protein complexes. Here we describe the fundamental mechanisms such as the hydrophobic insertion, scaffolding and crowding mechanisms these proteins use to produce membrane curvatures and complex shapes required to form intracellular organelles and vesicular structures involved in endocytosis and secretion. For each mechanism, we discuss its cellular functions as well as the underlying physical principles and the specific membrane properties required for the mechanism to be feasible. We propose that the integration of individual mechanisms into a highly controlled, robust process of curvature generation often relies on the assembly of proteins into coats. How cells unify and organize the curvature-generating factors at the nanoscale is presented for three ubiquitous coats central for membrane trafficking in eukaryotes: clathrin-coated pits, caveolae, and COPI and COPII coats. The emerging theme is that these coats arrange and coordinate curvature-generating factors in time and space to dynamically shape membranes to accomplish membrane trafficking within cells.
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Affiliation(s)
- Michael M Kozlov
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | - Justin W Taraska
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
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12
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Kahle ER, Patel N, Sreenivasappa HB, Marcolongo MS, Han L. Targeting cell-matrix interface mechanobiology by integrating AFM with fluorescence microscopy. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2022; 176:67-81. [PMID: 36055517 PMCID: PMC9691605 DOI: 10.1016/j.pbiomolbio.2022.08.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 08/14/2022] [Accepted: 08/18/2022] [Indexed: 06/15/2023]
Abstract
Mechanosensing at the interface of a cell and its surrounding microenvironment is an essential driving force of physiological processes. Understanding molecular activities at the cell-matrix interface has the potential to provide novel targets for improving tissue regeneration and early disease intervention. In the past few decades, the advancement of atomic force microscopy (AFM) has offered a unique platform for probing mechanobiology at this crucial microdomain. In this review, we describe key advances under this topic through the use of an integrated system of AFM (as a biomechanical testing tool) with complementary immunofluorescence (IF) imaging (as an in situ navigation system). We first describe the body of work investigating the micromechanics of the pericellular matrix (PCM), the immediate cell micro-niche, in healthy, diseased, and genetically modified tissues, with a focus on articular cartilage. We then summarize the key findings in understanding cellular biomechanics and mechanotransduction, in which, molecular mechanisms governing transmembrane ion channel-mediated mechanosensing, cytoskeleton remodeling, and nucleus remodeling have been studied in various cell and tissue types. Lastly, we provide an overview of major technical advances that have enabled more in-depth studies of mechanobiology, including the integration of AFM with a side-view microscope, multiple optomicroscopy, a fluorescence recovery after photobleaching (FRAP) module, and a tensile stretching device. The innovations described here have contributed greatly to advancing the fundamental knowledge of extracellular matrix biomechanics and cell mechanobiology for improved understanding, detection, and intervention of various diseases.
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Affiliation(s)
- Elizabeth R Kahle
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA 19104, United States
| | - Neil Patel
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA 19104, United States
| | - Harini B Sreenivasappa
- Cell Imaging Center, Office of Research and Innovation, Drexel University, PA 19104, United States
| | - Michele S Marcolongo
- Department of Mechanical Engineering, Villanova University, Villanova, PA 19085, United States
| | - Lin Han
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA 19104, United States.
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13
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Riley NM, Wen RM, Bertozzi CR, Brooks JD, Pitteri SJ. Measuring the multifaceted roles of mucin-domain glycoproteins in cancer. Adv Cancer Res 2022; 157:83-121. [PMID: 36725114 PMCID: PMC10582998 DOI: 10.1016/bs.acr.2022.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Mucin-domain glycoproteins are highly O-glycosylated cell surface and secreted proteins that serve as both biochemical and biophysical modulators. Aberrant expression and glycosylation of mucins are known hallmarks in numerous malignancies, yet mucin-domain glycoproteins remain enigmatic in the broad landscape of cancer glycobiology. Here we review the multifaceted roles of mucins in cancer through the lens of the analytical and biochemical methods used to study them. We also describe a collection of emerging tools that are specifically equipped to characterize mucin-domain glycoproteins in complex biological backgrounds. These approaches are poised to further elucidate how mucin biology can be understood and subsequently targeted for the next generation of cancer therapeutics.
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Affiliation(s)
- Nicholas M Riley
- Department of Chemistry and Sarafan ChEM-H, Stanford University, Stanford, CA, United States.
| | - Ru M Wen
- Department of Urology, Stanford University School of Medicine, Stanford, CA, United States
| | - Carolyn R Bertozzi
- Department of Chemistry and Sarafan ChEM-H, Stanford University, Stanford, CA, United States; Howard Hughes Medical Institute, Stanford, CA, United States
| | - James D Brooks
- Department of Urology, Stanford University School of Medicine, Stanford, CA, United States; Department of Radiology, Canary Center at Stanford for Cancer Early Detection, Stanford University School of Medicine, Palo Alto, CA, United States
| | - Sharon J Pitteri
- Department of Radiology, Canary Center at Stanford for Cancer Early Detection, Stanford University School of Medicine, Palo Alto, CA, United States.
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14
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Fifty Years of the Fluid–Mosaic Model of Biomembrane Structure and Organization and Its Importance in Biomedicine with Particular Emphasis on Membrane Lipid Replacement. Biomedicines 2022; 10:biomedicines10071711. [PMID: 35885016 PMCID: PMC9313417 DOI: 10.3390/biomedicines10071711] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 07/06/2022] [Accepted: 07/10/2022] [Indexed: 12/29/2022] Open
Abstract
The Fluid–Mosaic Model has been the accepted general or basic model for biomembrane structure and organization for the last 50 years. In order to establish a basic model for biomembranes, some general principles had to be established, such as thermodynamic assumptions, various molecular interactions, component dynamics, macromolecular organization and other features. Previous researchers placed most membrane proteins on the exterior and interior surfaces of lipid bilayers to form trimolecular structures or as lipoprotein units arranged as modular sheets. Such membrane models were structurally and thermodynamically unsound and did not allow independent lipid and protein lateral movements. The Fluid–Mosaic Membrane Model was the only model that accounted for these and other characteristics, such as membrane asymmetry, variable lateral movements of membrane components, cis- and transmembrane linkages and dynamic associations of membrane components into multimolecular complexes. The original version of the Fluid–Mosaic Membrane Model was never proposed as the ultimate molecular description of all biomembranes, but it did provide a basic framework for nanometer-scale biomembrane organization and dynamics. Because this model was based on available 1960s-era data, it could not explain all of the properties of various biomembranes discovered in subsequent years. However, the fundamental organizational and dynamic aspects of this model remain relevant to this day. After the first generation of this model was published, additional data on various structures associated with membranes were included, resulting in the addition of membrane-associated cytoskeletal, extracellular matrix and other structures, specialized lipid–lipid and lipid–protein domains, and other configurations that can affect membrane dynamics. The presence of such specialized membrane domains has significantly reduced the extent of the fluid lipid membrane matrix as first proposed, and biomembranes are now considered to be less fluid and more mosaic with some fluid areas, rather than a fluid matrix with predominantly mobile components. However, the fluid–lipid matrix regions remain very important in biomembranes, especially those involved in the binding and release of membrane lipid vesicles and the uptake of various nutrients. Membrane phospholipids can associate spontaneously to form lipid structures and vesicles that can fuse with various cellular membranes to transport lipids and other nutrients into cells and organelles and expel damaged lipids and toxic hydrophobic molecules from cells and tissues. This process and the clinical use of membrane phospholipid supplements has important implications for chronic illnesses and the support of healthy mitochondria, plasma membranes and other cellular membrane structures.
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The many faces of membrane tension: Challenges across systems and scales. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:183897. [PMID: 35231438 DOI: 10.1016/j.bbamem.2022.183897] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 02/09/2022] [Accepted: 02/16/2022] [Indexed: 01/27/2023]
Abstract
Our understanding of the role of membrane tension in the field of membrane biophysics is rapidly evolving from a passive construct to an active player in a variety of cellular phenomena. Membrane tension has been shown to be a key regulator of many cellular processes ranging including trafficking, ion channel activation, and the invasion of red blood cells by malaria parasites. Recent experimental advances in cells, including the development of a fluorescent tension reporter, have shown that membrane tension is heterogeneous. In this mini-review, I summarize the recent advances in membrane tension measurements and discuss the contributions from different cellular constituents such as the cortical cytoskeleton. Then, I will explore how these different complexities can be considered in biophysical models of different scales. Finally, I will elaborate on the need for iterations between models and experiments as technologies in both fields advance to enable us to obtain critical insights into the physiological role of membrane tension as a critical component of mechanotransduction.
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Nicolson GL, Ferreira de Mattos G. A Brief Introduction to Some Aspects of the Fluid-Mosaic Model of Cell Membrane Structure and Its Importance in Membrane Lipid Replacement. MEMBRANES 2021; 11:947. [PMID: 34940448 PMCID: PMC8708848 DOI: 10.3390/membranes11120947] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 11/18/2021] [Accepted: 11/22/2021] [Indexed: 12/15/2022]
Abstract
Early cell membrane models placed most proteins external to lipid bilayers in trimolecular structures or as modular lipoprotein units. These thermodynamically untenable structures did not allow lipid lateral movements independent of membrane proteins. The Fluid-Mosaic Membrane Model accounted for these and other properties, such as membrane asymmetry, variable lateral mobilities of membrane components and their associations with dynamic complexes. Integral membrane proteins can transform into globular structures that are intercalated to various degrees into a heterogeneous lipid bilayer matrix. This simplified version of cell membrane structure was never proposed as the ultimate biomembrane description, but it provided a basic nanometer scale framework for membrane organization. Subsequently, the structures associated with membranes were considered, including peripheral membrane proteins, and cytoskeletal and extracellular matrix components that restricted lateral mobility. In addition, lipid-lipid and lipid-protein membrane domains, essential for cellular signaling, were proposed and eventually discovered. The presence of specialized membrane domains significantly reduced the extent of the fluid lipid matrix, so membranes have become more mosaic with some fluid areas over time. However, the fluid regions of membranes are very important in lipid transport and exchange. Various lipid globules, droplets, vesicles and other membranes can fuse to incorporate new lipids or expel damaged lipids from membranes, or they can be internalized in endosomes that eventually fuse with other internal vesicles and membranes. They can also be externalized in a reverse process and released as extracellular vesicles and exosomes. In this Special Issue, the use of membrane phospholipids to modify cellular membranes in order to modulate clinically relevant host properties is considered.
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Affiliation(s)
- Garth L. Nicolson
- Department of Molecular Pathology, The Institute for Molecular Medicine, Huntington Beach, CA 92647, USA
| | - Gonzalo Ferreira de Mattos
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Department of Biophysics, Facultad de Medicina, Universidad de la República, Montevideo 11600, Uruguay;
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