1
|
Sciumè G, Guevorkian K, Nassoy P. A bi-component model to assess the rheology of soft cellular aggregates probed using the micropipette aspiration technique. Acta Biomater 2024; 189:449-460. [PMID: 39362447 DOI: 10.1016/j.actbio.2024.09.043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Revised: 09/21/2024] [Accepted: 09/24/2024] [Indexed: 10/05/2024]
Abstract
The micro-pipette aspiration technique is a classical experiment used to characterize the physical properties of inert fluids and biological soft materials such as cellular aggregates. The physical parameters of the fluid, as viscosity and interfacial tension, are obtained by studying how the fluid enters the pipette when the suction pressure is increased and how it relaxes when the suction pressure is put to zero. A mathematical model representative of the experiment is needed to extrapolate the physical parameters of the fluid-like matter; however, for biological materials as cells or cell aggregates mathematical models are always based on strong starting hypotheses that impact the significance of the identified parameters. In this article, starting from the bi-constituent nature of the cell aggregate, we derive a general mathematical model based of a Cahn-Hilliard-Navier-Stokes set of equations. The model is applied to describe quantitatively the aspiration-retraction dynamics of a cell-aggregate into and out of a pipette. We demonstrate the predictive capability of the model and highlight the impact of the assumptions made on the identified parameters by studying two cases: one with a non-wetting condition between the cells and the wall of the pipette (classical assumption in the literature) and the second one, which is more realistic, with a partial wetting condition (contact angle θs = 150°). Furthermore, our results provide a purely physical explanation to the asymmetry between the aspiration and retraction responses which is alternative to the proposed hypothesis of an mechano-responsive alteration of the surface tension of the cell aggregate. STATEMENT OF SIGNIFICANCE: Our study introduces a general mathematical model, based on the Cahn-Hilliard-Navier-Stokes equations, tailored to model micro-pipette aspiration of cell aggregates. The model accounts for the multi-component structure of the cell aggregate and its intrinsic viscoelastic rheology. By challenging prevailing assumptions, particularly regarding perfect non-wetting conditions and the mechano-responsive alteration of cell surface tension, we demonstrate the reliability of the mathematical model and elucidate the mechanisms at play, offering a purely physical explanation for observed asymmetries between the aspiration and retraction stages of the experiment.
Collapse
Affiliation(s)
- Giuseppe Sciumè
- University Bordeaux, CNRS, Bordeaux INP, I2M, UMR 5295, F-33400, Talence, France; Arts et Metiers Institute of Technology, CNRS, Bordeaux INP, Hesam Universite, I2M, UMR 5295, F-33400 Talence, France; Institut Universitaire de France (IUF), France.
| | - Karine Guevorkian
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Physique des Cellules et Cancer, 75005 Paris, France
| | - Pierre Nassoy
- LP2N, Laboratoire Photonique Numérique et Nanosciences, University Bordeaux, F-33400 Talence, France; Institut d'Optique Graduate School & CNRS UMR 5298, F-33400 Talence, France
| |
Collapse
|
2
|
Liao X, Li X, Liu R. Extracellular-matrix mechanics regulate cellular metabolism: A ninja warrior behind mechano-chemo signaling crosstalk. Rev Endocr Metab Disord 2023; 24:207-220. [PMID: 36385696 DOI: 10.1007/s11154-022-09768-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/21/2022] [Indexed: 11/18/2022]
Abstract
Mechanical forces are the indispensable constituent of environmental cues, such as gravity, barometric pressure, vibration, and contact with bodies, which are involved in pattern and organogenesis, providing mechanical input to tissues and determining the ultimate fate of cells. Extracellular matrix (ECM) stiffness, the slow elastic force, carries the external physical force load onto the cell or outputs the internal force exerted by the cell and its neighbors into the environment. Accumulating evidence illustrates the pivotal role of ECM stiffness in the regulation of organogenesis, maintenance of tissue homeostasis, and the development of multiple diseases, which is largely fulfilled through its systematical impact on cellular metabolism. This review summarizes the establishment and regulation of ECM stiffness, the mechanisms underlying how ECM stiffness is sensed by cells and signals to modulate diverse cell metabolic pathways, and the physiological and pathological significance of the ECM stiffness-cell metabolism axis.
Collapse
Affiliation(s)
- Xiaoyu Liao
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Research Unit of Oral Carcinogenesis and Management, Chinese Academy of Medical Sciences, West China Hospital of Stomatology, Sichuan University, 14, Section 3, Renminnan Road, Chengdu, 610041, Sichuan, China
| | - Xin Li
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Research Unit of Oral Carcinogenesis and Management, Chinese Academy of Medical Sciences, West China Hospital of Stomatology, Sichuan University, 14, Section 3, Renminnan Road, Chengdu, 610041, Sichuan, China
| | - Rui Liu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Research Unit of Oral Carcinogenesis and Management, Chinese Academy of Medical Sciences, West China Hospital of Stomatology, Sichuan University, 14, Section 3, Renminnan Road, Chengdu, 610041, Sichuan, China.
| |
Collapse
|
3
|
Li J, Wijeratne SS, Nelson TE, Lin TC, He X, Feng X, Nikoloutsos N, Fang R, Jiang K, Lian I, Kiang CH. Dependence of Membrane Tether Strength on Substrate Rigidity Probed by Single-Cell Force Spectroscopy. J Phys Chem Lett 2020; 11:4173-4178. [PMID: 32356665 DOI: 10.1021/acs.jpclett.0c00730] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Substrate rigidity modulates cell mechanics, which affect cell migration and proliferation. Quantifying the effects of substrate rigidity on cancer cell mechanics requires a quantifiable parameter that can be measured for individual cells, as well as a substrate platform with rigidity being the only variable. Here we used single-cell force spectroscopy to pull cancer cells on substrates varying only in rigidity, and extracted a parameter from the force-distance curves to be used to quantify the properties of membrane tethers. Our results showed that tether force increases with substrate rigidity until it reaches its asymptotic limit. The variations are similar for all three cancer cell lines studied, and the largest change occurs in the rigidity regions of softer tissues, indicating a universal response of cancer cell elasticity to substrate rigidity.
Collapse
Affiliation(s)
- Jingqiang Li
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
| | - Sithara S Wijeratne
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
| | - Tyler E Nelson
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
- Department of Biology, Lamar University, Beaumont, Texas 77710, United States
| | - Tsung-Cheng Lin
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
| | - Xin He
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
| | - Xuewen Feng
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
| | - Nicolas Nikoloutsos
- Department of Biology, Lamar University, Beaumont, Texas 77710, United States
| | - Raymond Fang
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
| | - Kevin Jiang
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
| | - Ian Lian
- Department of Biology, Lamar University, Beaumont, Texas 77710, United States
| | - Ching-Hwa Kiang
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
- Department of Bioengineering, Rice University, Houston, Texas 77005, United States
| |
Collapse
|
4
|
Li F, Mao X, Li F, Li M, Shen J, Ge Z, Fan C, Zuo X. Ultrafast DNA Sensors with DNA Framework-Bridged Hybridization Reactions. J Am Chem Soc 2020; 142:9975-9981. [PMID: 32369359 DOI: 10.1021/jacs.9b13737] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Intracellular DNA-based hybridization reactions generally occur under tension rather than in free states, which are spatiotemporally controlled in physiological conditions. However, how nanomechanical forces affect DNA hybridization efficiencies in in-vitro DNA assays, for example, biosensors or biochips, remains largely elusive. Here, we design DNA framework-based nanomechanical handles that can control the stretching states of DNA molecules. Using a pair of tetrahedral DNA framework (TDF) nanostructured handles, we develop bridge DNA sensors that can capture target DNA with ultrafast speed and high efficiency. We find that the rigid TDF handles bind two ends of a single-stranded DNA (ssDNA) and hold it in a stretched state, with an apparent stretching length comparable to its counterpart of double-stranded DNA (dsDNA) via atomic force microscopy measurement. The DNA stretching effect of ssDNA is then monitored using single-molecule fluorescence energy transfer (FRET), resulting in decreased FRET efficiency in the stretched ssDNA. By controlling the stretching state of ssDNA, we obtained significantly improved hybridization kinetics (within 1 min) and hybridization efficiency (∼98%) under the target concentration of 500 nM. The bridge DNA sensors demonstrated high sensitivity (1 fM), high specificity (single mismatch mutation discrimination), and high selectivity (suitable for the detection in serum and blood) under the target concentration of 10 nM. Controlling the stretching state of ssDNA shows great potential in biosensors, bioimaging, and biochips applications.
Collapse
Affiliation(s)
- Fengqin Li
- Institute of Molecular Medicine, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, School of Medicine and School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200127, China.,Division of Physical Biology and Bioimaging Center, CAS Key Laboratory of Interfacial Physics and Technology, Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Xiuhai Mao
- Institute of Molecular Medicine, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, School of Medicine and School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Fan Li
- Institute of Molecular Medicine, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, School of Medicine and School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Min Li
- Institute of Molecular Medicine, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, School of Medicine and School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Jianlei Shen
- Institute of Molecular Medicine, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, School of Medicine and School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Zhilei Ge
- Institute of Molecular Medicine, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, School of Medicine and School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Chunhai Fan
- Institute of Molecular Medicine, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, School of Medicine and School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Xiaolei Zuo
- Institute of Molecular Medicine, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, School of Medicine and School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200127, China
| |
Collapse
|
5
|
Zhang XF, Zhang W, Quach ME, Deng W, Li R. Force-Regulated Refolding of the Mechanosensory Domain in the Platelet Glycoprotein Ib-IX Complex. Biophys J 2019; 116:1960-1969. [PMID: 31030883 DOI: 10.1016/j.bpj.2019.03.037] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 03/25/2019] [Accepted: 03/29/2019] [Indexed: 12/18/2022] Open
Abstract
In platelets, the glycoprotein (GP) Ib-IX receptor complex senses blood shear flow and transmits the mechanical signals into platelets. Recently, we have discovered a juxtamembrane mechanosensory domain (MSD) within the GPIbα subunit of GPIb-IX. Mechanical unfolding of the MSD activates GPIb-IX signaling into platelets, leading to their activation and clearance. Using optical tweezer-based single-molecule force measurement, we herein report a systematic biomechanical characterization of the MSD in its native, full-length receptor complex and a recombinant, unglycosylated MSD in isolation. The native MSD unfolds at a resting rate of 9 × 10-3 s-1. Upon exposure to pulling forces, MSD unfolding accelerates exponentially over a force scale of 2.0 pN. Importantly, the unfolded MSD can refold with or without applied forces. The unstressed refolding rate of MSD is ∼17 s-1 and slows exponentially over a force scale of 3.7 pN. Our measurements confirm that the MSD is relatively unstable, with a folding free energy of 7.5 kBT. Because MSD refolding may turn off GPIb-IX's mechanosensory signals, our results provide a mechanism for the requirement of a continuous pulling force of >15 pN to fully activate GPIb-IX.
Collapse
Affiliation(s)
- X Frank Zhang
- Department of Bioengineering, Department of Mechanical Engineering & Mechanics, Lehigh University, Bethlehem, Pennsylvania.
| | - Wei Zhang
- Department of Bioengineering, Department of Mechanical Engineering & Mechanics, Lehigh University, Bethlehem, Pennsylvania
| | - M Edward Quach
- Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia
| | - Wei Deng
- Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia
| | - Renhao Li
- Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia.
| |
Collapse
|
6
|
Chu SY, Chou CH, Huang HD, Yen MH, Hong HC, Chao PH, Wang YH, Chen PY, Nian SX, Chen YR, Liou LY, Liu YC, Chen HM, Lin FM, Chang YT, Chen CC, Lee OK. Mechanical stretch induces hair regeneration through the alternative activation of macrophages. Nat Commun 2019; 10:1524. [PMID: 30944305 PMCID: PMC6447615 DOI: 10.1038/s41467-019-09402-8] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 03/04/2019] [Indexed: 12/28/2022] Open
Abstract
Tissues and cells in organism are continuously exposed to complex mechanical cues from the environment. Mechanical stimulations affect cell proliferation, differentiation, and migration, as well as determining tissue homeostasis and repair. By using a specially designed skin-stretching device, we discover that hair stem cells proliferate in response to stretch and hair regeneration occurs only when applying proper strain for an appropriate duration. A counterbalance between WNT and BMP-2 and the subsequent two-step mechanism are identified through molecular and genetic analyses. Macrophages are first recruited by chemokines produced by stretch and polarized to M2 phenotype. Growth factors such as HGF and IGF-1, released by M2 macrophages, then activate stem cells and facilitate hair regeneration. A hierarchical control system is revealed, from mechanical and chemical signals to cell behaviors and tissue responses, elucidating avenues of regenerative medicine and disease control by demonstrating the potential to manipulate cellular processes through simple mechanical stimulation.
Collapse
Affiliation(s)
- Szu-Ying Chu
- Department of Dermatology, Taipei Veterans General Hospital, Taipei, 112, Taiwan
- Institute of Clinical Medicine, National Yang-Ming University, Taipei, 112, Taiwan
- Department of Dermatology, National Yang-Ming University, Taipei, 112, Taiwan
| | - Chih-Hung Chou
- Department of Biological Science and Technology, Center for Intelligent Drug Systems and Smart Bio-devices (IDS2B), National Chiao Tung University, Hsinchu, 300, Taiwan
| | - Hsien-Da Huang
- Warshel Institute for Computational Biology, School of Life and Health Sciences, School of Sciences and Engineering, The Chinese University of Hong Kong, Shenzhen, 518172, China
| | - Meng-Hua Yen
- Department of Electronic Engineering, National Chin-Yi University of Technology, Taichung, 411, Taiwan
| | - Hsiao-Chin Hong
- Department of Biological Science and Technology, Institute of Bioinformatics and Systems Biology, National Chiao Tung University, Hsinchu, 300, Taiwan
| | - Po-Han Chao
- Institute of Clinical Medicine, National Yang-Ming University, Taipei, 112, Taiwan
| | - Yu-Hsuan Wang
- Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong, 999077, China
- Institute for Tissue Engineering and Regenerative Medicine, The Chinese University of Hong Kong, Hong Kong, 999077, China
| | - Po-Yu Chen
- Department of Dermatology, Taipei Veterans General Hospital, Taipei, 112, Taiwan
- Department of Dermatology, National Yang-Ming University, Taipei, 112, Taiwan
| | - Shi-Xin Nian
- Department of Dermatology, Taipei Veterans General Hospital, Taipei, 112, Taiwan
- Department of Dermatology, National Yang-Ming University, Taipei, 112, Taiwan
| | - Yu-Ru Chen
- Institute of Clinical Medicine, National Yang-Ming University, Taipei, 112, Taiwan
| | - Li-Ying Liou
- Department of Dermatology, Taipei Veterans General Hospital, Taipei, 112, Taiwan
- Department of Dermatology, National Yang-Ming University, Taipei, 112, Taiwan
| | - Yu-Chen Liu
- Department of Biological Science and Technology, Institute of Bioinformatics and Systems Biology, National Chiao Tung University, Hsinchu, 300, Taiwan
| | - Hui-Mei Chen
- Department of Biological Science and Technology, Institute of Bioinformatics and Systems Biology, National Chiao Tung University, Hsinchu, 300, Taiwan
| | - Feng-Mao Lin
- Department of Biological Science and Technology, Institute of Bioinformatics and Systems Biology, National Chiao Tung University, Hsinchu, 300, Taiwan
| | - Yun-Ting Chang
- Department of Dermatology, Taipei Veterans General Hospital, Taipei, 112, Taiwan
- Department of Dermatology, National Yang-Ming University, Taipei, 112, Taiwan
| | - Chih-Chiang Chen
- Department of Dermatology, Taipei Veterans General Hospital, Taipei, 112, Taiwan.
- Institute of Clinical Medicine, National Yang-Ming University, Taipei, 112, Taiwan.
- Department of Dermatology, National Yang-Ming University, Taipei, 112, Taiwan.
| | - Oscar K Lee
- Institute of Clinical Medicine, National Yang-Ming University, Taipei, 112, Taiwan.
- Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong, 999077, China.
- Institute for Tissue Engineering and Regenerative Medicine, The Chinese University of Hong Kong, Hong Kong, 999077, China.
| |
Collapse
|
7
|
Wijeratne SS, Nolasco L, Li J, Jiang K, Moake JL, Kiang CH. Correlating Conformational Dynamics with the Von Willebrand Factor Reductase Activity of Factor H Using Single Molecule Force Measurements. J Phys Chem B 2018; 122:10653-10658. [PMID: 30351116 DOI: 10.1021/acs.jpcb.8b06153] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Activation of proteins often involves conformational transitions, and these switches are often difficult to characterize in multidomain proteins. Full-length factor H (FH), consisting of 20 small consensus repeat domains (150 kD), is a complement control protein that regulates the activity of the alternative complement pathway. Different preparations of FH can also reduce the disulfide bonds linking large Von Willebrand factor (VWF) multimers into smaller, less adhesive forms. In contrast, commercially available purified FH (pFH) has little or no VWF reductase activity unless the pFH is chemically modified by either ethylenediaminetetraacetic acid (EDTA) or urea. We used atomic force microscopy single molecule force measurements to investigate different forms of FH, including recombinant FH and pFH, in the presence or absence of EDTA and urea, and to correlate the conformational changes to its activities. We found that the FH conformation depends on the method used for sample preparation, which affects the VWF reductase activity of FH.
Collapse
|
8
|
Staehlke S, Rebl H, Finke B, Mueller P, Gruening M, Nebe JB. Enhanced calcium ion mobilization in osteoblasts on amino group containing plasma polymer nanolayer. Cell Biosci 2018; 8:22. [PMID: 29588849 PMCID: PMC5863460 DOI: 10.1186/s13578-018-0220-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 03/14/2018] [Indexed: 11/23/2022] Open
Abstract
Background Biomaterial modifications—chemical and topographical—are of particular importance for the integration of materials in biosystems. Cells are known to sense these biomaterial characteristics, but it has remained unclear which physiological processes bio modifications trigger. Hence, the question arises of whether the dynamic of intracellular calcium ions is important for the characterization of the cell–material interaction. In our prior research we could demonstrate that a defined geometrical surface topography affects the cell physiology; this was finally detectable in a reduced intracellular calcium mobilization after the addition of adenosine triphosphate (ATP). Results This new contribution examines the cell physiology of human osteoblasts concerning the relative cell viability and the calcium ion dynamic on different chemical modifications of silicon–titanium (Ti) substrates. Chemical modifications comprising the coating of Ti surfaces with a plasma polymerized allylamine (PPAAm)-layer or with a thin layer of collagen type-I were compared with a bare Ti substrate as well as tissue culture plastic. For this purpose, the human osteoblasts (MG-63 and primary osteoblasts) were seeded onto the surfaces for 24 h. The relative cell viability was determined by colorimetric measurements of the cell metabolism and relativized to the density of cells quantified using crystal violet staining. The calcium ion dynamic of osteoblasts was evaluated by the calcium imaging analysis of fluo-3 stained vital cells using a confocal laser scanning microscope. The positively charged nano PPAAm-layer resulted in enhanced intracellular calcium ion mobilization after ATP-stimulus and cell viability. This study underlines the importance of the calcium signaling for the manifestation of the cell physiology. Conclusions Our current work provides new insights into the intracellular calcium dynamic caused by diverse chemical surface compositions. The calcium ion dynamic appears to be a sensitive parameter for the cell physiology and, thus, may represent a useful approach for evaluating a new biomaterial. In this regard, reliable in vitro-tests of cell behavior at the interface to a material are crucial steps in securing the success of a new biomaterial in medicine.
Collapse
Affiliation(s)
- Susanne Staehlke
- Dept. of Cell Biology, University Medical Center Rostock, Schillingallee 69, 18057 Rostock, Germany
| | - Henrike Rebl
- Dept. of Cell Biology, University Medical Center Rostock, Schillingallee 69, 18057 Rostock, Germany
| | - Birgit Finke
- 2Leibniz-Institute for Plasma Science and Technology (INP), Felix-Hausdorff-Str. 2, 17489 Greifswald, Germany
| | - Petra Mueller
- Dept. of Cell Biology, University Medical Center Rostock, Schillingallee 69, 18057 Rostock, Germany
| | - Martina Gruening
- Dept. of Cell Biology, University Medical Center Rostock, Schillingallee 69, 18057 Rostock, Germany
| | - J Barbara Nebe
- Dept. of Cell Biology, University Medical Center Rostock, Schillingallee 69, 18057 Rostock, Germany
| |
Collapse
|
9
|
Stretch your heart-but not too far: The role of titin mutations in dilated cardiomyopathy. J Thorac Cardiovasc Surg 2018; 156:209-214. [PMID: 29685583 DOI: 10.1016/j.jtcvs.2017.10.160] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 09/29/2017] [Accepted: 10/24/2017] [Indexed: 12/23/2022]
|
10
|
Duncan R. Polymer therapeutics at a crossroads? Finding the path for improved translation in the twenty-first century. J Drug Target 2017; 25:759-780. [PMID: 28783978 DOI: 10.1080/1061186x.2017.1358729] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Despite the relatively small early investment, first generation 'polymer therapeutics' have been remarkably successful with more than 25 products licenced for human use as polymeric drugs, sequestrants, conjugates, and as an imaging agent. Many exhibit both clinical and commercial success with new concepts already in clinical trials. Nevertheless after four decades of evolution, this field is arriving at an important crossroads. Over the last decade, the landscape has changed rapidly. There are an increasing number of failed clinical trials, the number of 'copy' and 'generic' products is growing (danger of ignoring the biological rationale for design and suppression of innovation), potential drawbacks of PEG are becoming more evident, and the 'nanomedicine' boom has brought danger of loss of scientific focus/hype. Grasping opportunities provided by advances in understanding of the patho-physiology and molecular basis of diseases, new polymer/conjugate synthetic and analytical methods, as well as the large database of clinical experience will surely ensure a successful future for innovative polymer therapeutics. Progress will, however, be in jeopardy if polymer safety is overlooked in respect of the specific route of administration/clinical use, poorly characterised materials/formulations are used to define biological or early clinical properties, and if clinical trial protocols fail to select patients most likely to benefit from these macromolecular therapeutics. Opportunities to improve clinical trial design for polymer-anticancer drug conjugates are discussed. This short personal perspective summarises some of the important challenges facing polymer therapeutics in R&D today, and future opportunities to improve successful translation.
Collapse
Affiliation(s)
- Ruth Duncan
- a Polymer Therapeutics Laboratory , Centro de Investigación Príncipe Felipe , Valencia , Spain.,b Intracellular Delivery Solutions Laboratory, Faculty of Engineering and Science , University of Greenwich , Kent , UK
| |
Collapse
|
11
|
Lo YP, Liu YS, Rimando MG, Ho JHC, Lin KH, Lee OK. Three-dimensional spherical spatial boundary conditions differentially regulate osteogenic differentiation of mesenchymal stromal cells. Sci Rep 2016; 6:21253. [PMID: 26884253 PMCID: PMC4756701 DOI: 10.1038/srep21253] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2015] [Accepted: 01/20/2016] [Indexed: 01/09/2023] Open
Abstract
The spatial boundary condition (SBC) arising from the surrounding microenvironment imposes specific geometry and spatial constraints that affect organogenesis and tissue homeostasis. Mesenchymal stromal cells (MSCs) sensitively respond to alterations of mechanical cues generated from the SBC. However, mechanical cues provided by a three-dimensional (3D) environment are deprived in a reductionist 2D culture system. This study investigates how SBC affects osteogenic differentiation of MSCs using 3D scaffolds with monodispersed pores and homogenous spherical geometries. MSCs cultured under SBCs with diameters of 100 and 150 μm possessed the greatest capability of osteogenic differentiation. This phenomenon was strongly correlated with MSC morphology, organization of actin cytoskeleton, and distribution of focal adhesion involving α2 and α5 integrins. Further silencing either α2 or α5 integrin significantly reduced the above mentioned mechanosensitivity, indicating that the α2 and α5 integrins as mechano-sensitive molecules mediate MSCs' ability to provide enhanced osteogenic differentiation in response to different spherical SBCs. Taken together, the findings provide new insights regarding how MSCs respond to mechanical cues from the surrounding microenvironment in a spherical SBC, and such biophysical stimuli should be taken into consideration in tissue engineering and regenerative medicine in conjunction with biochemical cues.
Collapse
Affiliation(s)
- Yin-Ping Lo
- Program in Molecular Medicine, National Yang-Ming University and Academia Sinica, Taipei 11221, Taiwan
| | - Yi-Shiuan Liu
- Stem Cell Research Center, National Yang-Ming University, Taipei 11221, Taiwan
| | - Marilyn G Rimando
- Taiwan International Graduate Program in Molecular Medicine, National Yang-Ming University and Academia Sinica, Taipei 11221, Taiwan
| | - Jennifer Hui-Chun Ho
- Center for Stem Cell Research, Wan Fang Hospital, Taipei Medical University, Taipei 11696, Taiwan.,Graduate Institute of Clinical Medicine, Taipei Medical University, Taipei 11031, Taiwan.,Department of Ophthalmology, Wan Fang Hospital, Taipei Medical University, Taipei 11696, Taiwan
| | - Keng-Hui Lin
- Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
| | - Oscar K Lee
- Taipei City Hospital, Taipei 10341, Taiwan.,Institute of Clinical Medicine, National Yang-Ming University, Taipei 11221, Taiwan.,Department of Orthopaedics and Traumatology, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| |
Collapse
|
12
|
Hu S, Tee YH, Kabla A, Zaidel-Bar R, Bershadsky A, Hersen P. Structured illumination microscopy reveals focal adhesions are composed of linear subunits. Cytoskeleton (Hoboken) 2015; 72:235-45. [PMID: 26012525 DOI: 10.1002/cm.21223] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Revised: 04/14/2015] [Accepted: 05/08/2015] [Indexed: 12/25/2022]
Abstract
The ability to mechanically interact with the extracellular matrix is a fundamental feature of adherent eukaryotic cells. Cell-matrix adhesion in many cell types is mediated by protein complexes called focal adhesions (FAs). Recent progress in super resolution microscopy revealed FAs possess an internal organization, yet such methods do not enable observation of the formation and dynamics of their internal structure in living cells. Here, we combine structured illumination microscopy (SIM) with total internal reflection fluorescence microscopy (TIRF) to show that the proteins inside FA patches are distributed along elongated subunits, typically 300 ± 100 nm wide, separated by 400 ± 100 nm, and individually connected to actin cables. We further show that the formation and dynamics of these linear subunits are intimately linked to radial actin fiber formation and actomyosin contractility. We found FA growth to be the result of nucleation of new linear subunits and their coordinated elongation. Taken together, this study reveals that the basic units of mature focal adhesion are 300-nm-wide elongated, dynamic structures. We anticipate this ultrastructure to be relevant to investigation of the function of FAs and their behavior in response to mechanical stress.
Collapse
Affiliation(s)
- Shiqiong Hu
- The Mechanobiology Institute, National University of Singapore, 5A Engineering Drive 1, Singapore, 117411, Singapore
| | - Yee-Han Tee
- The Mechanobiology Institute, National University of Singapore, 5A Engineering Drive 1, Singapore, 117411, Singapore
| | - Alexandre Kabla
- The Mechanobiology Institute, National University of Singapore, 5A Engineering Drive 1, Singapore, 117411, Singapore
- Engineering Department, Cambridge University, Trumpington Street, Cambridge, CB2 1PZ, UK
| | - Ronen Zaidel-Bar
- The Mechanobiology Institute, National University of Singapore, 5A Engineering Drive 1, Singapore, 117411, Singapore
| | - Alexander Bershadsky
- The Mechanobiology Institute, National University of Singapore, 5A Engineering Drive 1, Singapore, 117411, Singapore
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Pascal Hersen
- The Mechanobiology Institute, National University of Singapore, 5A Engineering Drive 1, Singapore, 117411, Singapore
- Laboratoire Matière et Systèmes Complexes, UMR 7057 CNRS and Université Paris Diderot, 10 Rue Alice Domon et Léonie Duquet, Paris, 75013, France
| |
Collapse
|