Mechanotransduction (eBook)

Adam J. Engler, Sanjay Kumar (Herausgeber)

eBook Download: PDF | EPUB

2014 | 1. Auflage
384 Seiten
Elsevier Science (Verlag)
978-0-12-398327-5 (ISBN)

Infos

Progress in Molecular Biology and Translational Science provides a forum for discussion of new discoveries, approaches, and ideas in molecular biology. It contains contributions from leaders in their fields and abundant references. Volume 126 features in-depth reviews that focus on the tools required to investigate mechanotransduction. Additional chapters focus on how we can use these tools to answer fundamental questions about the interaction of physical forces with cell biology, morphogenesis, and function of mature structures. Chapters in the volume are authored by a unique combination of cell biologists and engineers, providing a range of perspectives on mechanotransduction. - Provides a unique combination of perspectives from biologists and engineers - Engaging to people of many training backgrounds

Inhalt

Front Cover 1
Mechanotransduction 4
Copyright 5
Contents 6
Contributors 12
Preface 14
Part One: Subcellular Tools for Activating and Measuring Mechanotransductive Signaling 16
Chapter One: The Detection and Role of Molecular Tension in Focal Adhesion Dynamics 18
1. Brief Introduction to Mechanobiology 19
2. Focal Adhesions in Mechanosensing 20
2.1. Focal adhesion structure 20
2.2. Molecular mechanisms of mechanotransduction 21
3. Design and Use of Optically Based Molecular Tension Sensors 24
3.1. Basics of Forster Resonance Energy Transfer (FRET) 24
3.2. Designs of FRET-based force-sensitive biosensors 26
3.2.1. Extensible domain 26
3.2.2. Rotatable domain 28
3.2.3. Other designs 28
3.3. Use of FRET-based tension sensors: Relative versus absolute measurements 29
3.4. Critical control experiments and assumptions involved in the creation and use of FRET-based biosensors 30
3.5. Conformation sensors versus tension sensors 31
4. The Role of Molecular Tension in Focal Adhesion Dynamics 31
5. Future Outlook 34
Acknowledgments 34
References 34
Chapter Two: Single-Cell Imaging of Mechanotransduction in Endothelial Cells 40
1. Introduction 41
2. Atherosclerosis, EC Wound Healing, and Mechanotransduction 42
3. Signaling Molecules Involved in Mechanosensing and Mechanotransduction 44
4. The Effect of Subcellular Structure on Mechanotransduction 45
5. Focal Adhesion and FAK 50
6. Tools to Monitor Signal Transduction in Live Cells 51
6.1. FPs, FRET, and fluorescence lifetime imaging microscopy 51
6.2. Quantitative image-based analysis for live cells 52
6.3. The FRAP analysis and finite-element-based diffusion analysis 52
6.4. Automatic tracking of moving cells and subcellular features 53
7. Conclusion 55
References 56
Part Two: Focal Adhesions as Sensors 68
Chapter Three: Focal Adhesions Function as a Mechanosensor 70
1. Introduction: The Basic Organization of Focal Adhesions 70
2. Mechanosensitivity of Focal Adhesions 74
3. Focal Adhesions and the Effects of Environmental Parameters 80
4. Focal Adhesion Signals and Cell Migration 81
Acknowledgments 82
References 83
Chapter Four: Mechanosensation: A Basic Cellular Process 90
1. Introduction 91
1.1. Historical development 91
1.2. Mechanosensation/-transduction 91
1.3. Effects of extracellular matrix stiffness 92
1.4. Stress generated by external compression/contractility 93
1.5. Stress generated by cell contractility 94
1.6. Biological relevance of external and internal stress 94
2. Focal Adhesions 97
2.1. Mechanotransduction/-signaling 99
2.2. Focal adhesion proteins 99
2.2.1. Vinculin 99
2.2.2. Zyxin 100
2.2.3. Talin 100
2.2.4. Paxillin, Pyk2 101
2.2.5. p130Cas 101
2.2.6. Focal adhesion kinase 101
2.3. Force transduction at focal adhesions 102
2.4. Protein crosstalk 106
2.5. Cell signaling pathways 106
2.6. Translation of information gathered at focal adhesions 107
2.7. Focal adherence junctions 107
2.8. Measuring mechanotransduction/-sensation 108
2.8.1. Flow chambers and cone and plate rheometers 108
2.8.2. Magnetic and optical traps 108
2.8.3. Atomic force microscopy and biomembrane force probe 108
2.8.4. Cell stretcher 109
2.8.5. Hydrostatic pressure 109
2.8.6. Stretch-activated ion channels 109
3. Conclusions 110
Acknowledgments 111
References 111
Chapter Five: Mechanical Cues Direct Focal Adhesion Dynamics 118
1. Introduction 119
2. Form and Function of Focal Adhesions 121
2.1. Influence of the ECM 121
2.2. Integrins are integral 124
2.3. Formation of focal adhesions 124
2.4. Cytoskeletal interplay 127
3. AFM as a Tool to Stimulate a Cellular Response 130
3.1. Cytoskeletal strain directs focal adhesion formation 131
3.2. Forces and substrate elasticity influence traction 135
4. Future Directions 142
Acknowledgments 143
References 143
Chapter Six: Molecular Mechanisms Underlying the Force-Dependent Regulation of Actin-to-ECM Linkage at the Focal Adhesions 150
1. Introduction 151
2. Molecular Assembly in the Actin-Integrin-ECM Linkage 152
2.1. Formation of the initial linkage 152
2.2. Force-dependent maturation of the linkage 153
3. Force-Sensing/Transducing Molecules in the Regulation of the Actin-Integrin-ECM Linkage 155
3.1. Talin and vinculin 155
3.1.1. Force-dependent vinculin binding with talin 155
3.1.2. The talin-vinculin binding in strengthening of the actin-integrin linkage 157
3.2. Zyxin, filamin, and actin assembly 158
3.2.1. Zyxin-dependent actin polymerization 159
3.2.2. Filamin and bundling of actin filaments 159
3.3. Integrin-fibronectin binding 160
4. Dynamic Aspect of the Actin-Integrin-ECM Linkage: Molecular Clutch 161
5. Concluding Remarks 163
Acknowledgments 164
References 164
Part Three: Nuclear Mechanisms of Sensing 170
Chapter Seven: The Cellular Mastermind(?)-Mechanotransduction and the Nucleus 172
1. Introduction 174
2. Overview of Nuclear Structure and Organization 176
2.1. Chromatin and chromosome territories 177
2.2. Subnuclear structures and nuclear bodies 180
2.3. The nucleoskeleton 181
2.4. Lamins, the nuclear lamina, and nuclear mechanics 182
2.5. Lamin-binding proteins 185
2.6. Nuclear membranes and nuclear pore complexes 186
2.7. LINC complexes 187
3. Mechanically Induced Changes in Nuclear Structure 189
3.1. Nuclear deformation during cell migration 189
3.2. Nuclear deformation under shear stress 191
3.3. Nuclear deformation under compression 191
3.4. Nuclear deformation under strain application 192
3.5. Substrate stiffness and patterning 192
3.6. Micromanipulation 192
4. Potential Mechanisms for Direct Nuclear Mechanosensing 193
5. Mechanotransduction Signaling in the Nucleus 195
5.1. MAPK/ERK/Fos 197
5.2. Wnt signaling 198
5.3. TGF-ß and Smad signaling 198
5.4. MKL1/SRF signaling 199
5.5. YAP/TAZ signaling 200
5.6. Interaction of retinoblastoma protein, lamins A/C, and LAP2a 201
5.7. Phosphorylation of nuclear envelope proteins 201
6. Functional Consequences of Impaired Mechanotransduction and Disease 202
6.1. Muscular dystrophy 203
6.2. Dilated cardiomyopathy 204
6.3. Hutchinson-Gilford progeria syndrome 204
7. Open Questions and Future Research Directions 205
8. Conclusions 206
Acknowledgments 208
References 208
Chapter Eight: Nuclear Forces and Cell Mechanosensing 220
1. Introduction 220
2. Cytoskeletal Forces are Exerted on the Nucleus 221
3. The LINC Complex Transmits Cytoskeletal Forces to the Nuclear Surface 223
4. The Role of the Nucleus in Cell Mechanosensing 225
5. Conclusions 226
Acknowledgments 226
References 227
Part Four: Mechano-Sensing in Stem Cells 232
Chapter Nine: From Stem Cells to Cardiomyocytes: The Role of Forces in Cardiac Maturation, Aging, and Disease 234
1. Introduction 235
2. Cardiac Morphogenesis During the Lifespan of the Heart 236
2.1. Specification, differentiation, and heart morphogenesis 236
2.2. Cell maturation and maintenance 236
3. Mechanosensitive Compartments in Cardiomyocytes 237
4. The Sarcomere 238
4.1. Cardiac structure and mechanosignaling 238
4.2. Sarcomere mutations, microenvironmental changes, and their impact 240
5. Other Intracellular Mechanosensitive Structures 241
5.1. Actin-associated intercalated disc and costameric proteins 241
5.2. Intermediate filament and microtubule networks 243
5.3. The cardiomyocyte membrane 244
6. ECM and Mechanosensing 244
7. The Influence of Mechanotransduction on Applications of Cardiac Regeneration 245
8. Conclusion 246
References 247
Chapter Ten: Matrix Regulation of Tumor-Initiating Cells 258
1. Introduction 259
1.1. What are tumor-initiating cells? 259
1.2. Significance of TICs 260
2. Identification and Isolation of TICs 262
3. Role of Extracellular Matrix and Mechanical Signals in Regulating TIC Function 262
3.1. Extracellular matrix 262
3.2. Propagation of TICs in ECM-adherent cultures 264
3.3. Mechanisms of mechanotransduction 265
4. Conclusion 266
References 267
Chapter Eleven: Biomaterials Approaches in Stem Cell Mechanobiology 272
1. Introduction 273
2. Mechanical Regulation of Stem Cell Fate 274
2.1. Tensional homeostasis and the origins of cellular force 274
2.2. Matrix stiffness, cell shape, and tension as regulators of stem cell fate 276
3. Mechanosensing and Mechanotransduction 280
3.1. Focal adhesions as mechanical sensors 280
3.2. Integrin-mediated mechanical signaling 281
3.3. Mechanically responsive ion channels, chromatin remodeling, and transcription factors 281
4. Pushing Ahead: Biomaterials Approaches to Probe Stem Cell Mechanobiology 284
4.1. Resolving interactions between mechanical and molecular signals 284
4.2. Controlling mechanics in space and time 286
5. Summary and Outlook 287
References 288
Part Five: Multi-Cellular Sensing 294
Chapter Twelve: Mechanotransduction in C. elegans Morphogenesis and Tissue Function 296
1. Intracellular Sensation and Response to Mechanical Input 297
1.1. Introduction 297
1.2. Mechanical influences in the C. elegans zygote 298
1.3. Cell shape changes 300
1.4. Nuclear response 300
2. Mechanical Influences in Embryonic Development 301
2.1. C. elegans integrins and mechanotransduction 302
2.2. Mechanical stability and attachment to apical ECM 302
2.3. Introduction to cell-cell junctions in C. elegans 304
2.4. Role of adherens junctions in C. elegans embryonic elongation 305
2.5. Mechanical coordination between tissues 308
3. Mechanical Influences in Larval Development and Tissue Function 310
3.1. Excretory canal development 310
3.2. Mechanical inputs into spermathecal function 312
4. Tools for Manipulation and Imaging 316
4.1. FRET-based sensors 316
4.2. Optogenetics 317
5. Future Prospects 319
Acknowledgments 320
References 320
Chapter Thirteen: Mechanical Force Sensing in Tissues 332
1. Introduction: Molecular Mechanisms of Multicellular Force Sensing 333
1.1. Force sensing by adhesion complexes 334
1.2. Force sensing by actomyosin networks 335
1.3. Force sensing by the cell plasma membrane 338
1.4. Force sensing by change in cell geometry 339
2. Multicellular Sensing During Tissue Growth 340
2.1. Mechanical regulation of tissue growth 341
2.2. Mechanical regulation of cell growth orientation 345
3. Multicellular Sensing During Tissue Morphogenesis 349
3.1. Mechanical coordination of actomyosin contractility 349
3.2. Mechanical reinforcement of junctions 354
3.3. Extrinsic mechanical constraints influencing tissue shape 356
Acknowledgments 359
References 359
Index 368
Color Plate 381

Textauszug

Chapter One

The Detection and Role of Molecular Tension in Focal Adhesion Dynamics

Brenton D. Hoffman    Department of Biomedical Engineering, Duke University, Durham, North Carolina, USA

Abstract

Cells are exquisitely sensitive to the mechanical nature of their environment, including applied force and the stiffness of the extracellular matrix (ECM). Recent evidence has shown that these variables are critical regulators of diverse processes mediating embryonic development, adult tissue physiology, and many disease states, including cancer, atherosclerosis, and myopathies. Often, detection of mechanical stimuli is mediated by the structures that link cells that surround ECM, the focal adhesions (FAs). FAs are intrinsically force sensitive and display altered dynamics, structure, and composition in response to applied load. While much progress has been made in determining the proteins that localize to and regulate the formation of these structures, less is known about the role of tension across specific proteins in this process. A recently developed class of force-sensitive biosensors is enabling a greater understanding of the molecular bases of cellular mechanosensitivity and cell migration.

Keywords

Mechanotransduction

Mechanobiology

Cell migration, Focal adhesions

Forster Resonance Energy Transfer

Tension sensor

Vinculin

1 Brief Introduction to Mechanobiology

The mechanical nature of the cellular microenvironment is increasingly recognized as a key determinant of many developmental, physiological, and pathophysiological processes1–6 as well as an important variable in tissue engineering and regenerative medicine.7–9 In vivo cells adhere to a deformable extracellular matrix (ECM) that is both a source of applied forces and a means of mechanical support.10–12 Cells detect, interpret, and respond to these mechanical signals through a poorly understood process called mechanotransduction.13,14 Mechanosensitive signaling affects several fundamental cellular processes, including cell contraction,15 migration,16 differentiation,17 and growth.18 For instance, during gastrulation in Drosophila melanogaster, germband extension causes compression of the stomodeal cells required for subsequent tissue invagination.19 Similarly, mechanical effects also mediate many physiological principles. These include Wolfe's law, which describes how mechanical loading leads to enhanced bone formation to enable adaptation of the skeleton,20 as well as the Bayliss effect, which describes the reduction in the diameter of arterioles after a pressure increase to maintain constant flow in downstream capillaries.21

Pathological mechanotransduction, often due to alterations in the mechanical nature of the microenvironment, is critically important in many prevalent and poorly understood human diseases.4,6,22 Inside the vasculature, cyclic blood flow leads to dynamic shear stresses on endothelial cells and alterations in blood pressure, stretching the vessel wall. Atherosclerotic lesions preferentially form in areas with perturbed hemodynamics and reduced forces applied to cells. Tumors are characterized by enhanced cell growth and perturbed ECM structure, leading to changes in the local tissue stiffness.15 These alterations in mechanical properties enable palpation exams for “lumps” as a common method of tumor detection. Recently, these rigidity changes have been shown to have a causative role in tumor progression.23

Traditionally, biological regulation has been understood through the principles of solution chemistry; reaction rates, diffusion, and binding affinities have been considered the dominant molecular scale variables. A central premise of biochemistry is that protein structure dictates function, suggesting that the diverse properties exhibited by proteins are due to their intricate three-dimensional shapes. A significant challenge in the field of mechanobiology is determining how macroscale mechanical variables alter molecular scale biochemical processes.24 A major advance was the demonstration that proteins are deformable at forces that can be generated by cells.25–27 Thus, a simple mechanism for mechanotransduction is that applied load alters protein structure, leading to novel functions. While many ground-breaking studies have enumerated the changes in cell signaling or protein expression after mechanical stimulation,28,29 relatively few have focused on determining the relationship between protein deformation and alterations in biochemical properties, such as differential enzymatic activity or binding lifetimes, in living cells. Recently, a new class of biosensor has been developed that reports the deformation within or the tension across specific proteins in living cells.30–32 These have started to reveal some of the molecular mechanisms mediating mechanotransduction, particularly in the context of adhesion biology.

In this article, I first review mechanosensitive behavior in the subcellular structure most associated with mechanosensitive phenomena, the focal adhesion (FA).33 We divide this process into mechanotransmission, mechanosensing, and mechanoresponse and briefly highlight critical molecular determinants of each step. Then, I discuss issues associated with the development and use of force-sensitive biosensors. I also describe recent advances in the understanding of the force-sensitive regulation of FA dynamics made possible by the development of these new sensors. I end by highlighting several future experiments that would further our understanding of the biophysical and biochemical processes mediating mechanotransduction.

2 Focal Adhesions in Mechanosensing

2.1 Focal adhesion structure

While the signaling pathways mediating mechanotransduction are still being elucidated, important subcellular structures have been identified.34 These include the structures that cells utilize to interact with the ECM, FAs.35 FAs are dynamic mechanosensitive scaffolds containing > 150 proteins that mechanically link the ECM and actin cytoskeleton.36,37 Connections to the ECM are mediated by integrins, heterodimeric transmembrane proteins which mediate cell adhesion through conformational regulation.38 Integrins primarily mediate changes in FA structure through the direct and indirect recruitment of proteins. Recent work using super-resolution microscopy with enhanced resolution in the vertical direction has shown that the proteins within FAs are arranged in a weakly stratified structure, comprising an integrin signaling layer, a force transduction layer, an actin regulatory layer, and finally actin-based stress fibers. The stress fibers simultaneously load the FA with forces generated by the cytoskeleton and resist deformation due to the application of external loads39 (Fig. 1.1). The cytoplasmic domains of integrins mediate interactions with numerous adaptor proteins (e.g., talin, paxillin, kindlin) and recruit, directly or indirectly, a host of signaling proteins (e.g., FA kinase, Src family kinases) to comprise the integrin signaling layer. The force transmission layer comprises many additional adaptor proteins (e.g., vinculin, talin, zyxin) that enable the dynamic and biochemically regulated transmission of force between the other layers. These proteins bind to a host of actin regulatory proteins (e.g., VASP) and actin cross-linking proteins (e.g, actinin) that mediate formation and reinforcement of the actin stress fibers. Note that some proteins exist in multiple layers. Talin, for instance, is thought to be oriented at an angle to link multiple layers.39

Figure 1.1 The stratified structure of a focal adhesion (FA). Integrins are transmembrane proteins that bind to the ECM and several intracellular proteins, including paxillin and FAK. Many of the proteins found near the plasma membrane are signaling proteins, which determine the activation state and binding partners of integrins. Slightly higher in the FA reside many adaptor proteins whose main functions are to transmit force between the layers and transduce these forces into biochemically detectable signals. Key elements include talin and vinculin. Higher still is a layer of proteins associated with actin regulation. This class is typified by VASP. At the highest point, the FA links to actin stress fibers. These layers work in concert to regulating the mechanosensitive behavior of the FA.

2.2 Molecular mechanisms of mechanotransduction

Descriptions of mechanotransduction typically involve three distinct steps: transmission of the applied load to specialized structures, transduction of the force into a biochemically detectable signal, and the subsequent response of the cell13,40 (Fig. 1.2). These are commonly referred to as mechanotransmission, mechanosensing, and mechanoresponse, respectively. Here, I focus on the first two steps. Mechanoresponses, including the long-term adaptation of cellular adhesion structures and the actin cytoskeleton, activation of transcription factors leading differential protein expression, as well as many physiological processes mediating tissue homeostasis in response to mechanical perturbations, are not necessarily force-dependent and have been extensively reviewed...

Produkt-Details

• Erscheint lt. Verlag: 29.7.2014
• Sprache: englisch
• Themenwelt: Studium ► 1. Studienabschnitt (Vorklinik) ► Physiologie
• Themenwelt: Naturwissenschaften ► Biologie ► Genetik / Molekularbiologie
• Themenwelt: Naturwissenschaften ► Biologie ► Zellbiologie
• ISBN-10: 0-12-398327-4 / 0123983274
• ISBN-13: 978-0-12-398327-5 / 9780123983275