UC San Diego Electronic Theses and Dissertations
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UC San Diego UC San Diego Electronic Theses and Dissertations Title Biomechanical implications of muscle cell-ECM communication Permalink https://escholarship.org/uc/item/8qf1428m Author Meyer, Gretchen Ann Publication Date 2011 Peer reviewed|Thesis/dissertation eScholarship.org Powered by the California Digital Library University of California UNIVERSITY OF CALIFORNIA, SAN DIEGO Biomechanical Implications of Muscle Cell-ECM Communication A dissertation submitted in partial satisfaction of the requirements for the degree Doctor of Philosophy in Bioengineering by Gretchen Ann Meyer Committee in charge: Professor Richard L. Lieber, Chair Professor Andrew D. McCulloch, Co-Chair Professor Anne Hoger Professor Geert Schmid-Schonbein Professor Samuel R. Ward 2011 Copyright Gretchen Ann Meyer, 2011 All rights reserved. The dissertation of Gretchen Ann Meyer is approved, and it is acceptable in quality and form for publication on microfilm and electronically: Co-Chair Chair University of California, San Diego 2011 iii DEDICATION This work is dedicated to my parents whose constant and unconditional support has always made me feel invincible. And to my colleagues and friends whose light has guided me through this mysterious world of science. iv EPIGRAPH Muscle is a metaphor for life; sometimes we could all use a good stretch. v TABLE OF CONTENTS Signature Page . iii Dedication . iv Epigraph . .v Table of Contents . vi List of Figures . .x List of Tables . xiii Acknowledgements . xiv Vita........................................ xvi Abstract of the Dissertation . xviii Chapter 1 Introduction . .1 1.1 Structure and function in skeletal muscle . .1 1.1.1 Extracellular structure . .2 1.1.2 Intracellular structure . .3 1.2 Desmin in muscle physiology . .6 1.3 Clinical relevance . .8 1.4 Summary . 10 1.5 References . 10 Chapter 2 Theoretical Predictions of the Effects of Force Transmission by Desmin on Intersarcomere Dynamics . 14 2.1 Introduction . 15 2.2 Methods . 16 2.2.1 The sarcomere finite element . 16 2.2.2 Equations of motion . 18 2.2.3 Model parameters . 21 2.2.4 The contractile element . 22 2.2.5 The parallel viscoelastic element . 23 2.2.6 Variation in sarcomere properties . 23 2.2.7 Properties of the ECM and tendon . 25 2.2.8 Desmin stiffness . 25 2.2.9 Simulations . 25 2.3 Results . 27 2.3.1 Passive stretch . 27 vi 2.3.2 Fixed end contraction . 27 2.4 Discussion . 32 2.5 References . 37 Chapter 3 Elucidation of Extracellular Matrix Mechanics from Muscle Fibers and Fiber Bundles . 41 3.1 Introduction . 42 3.2 Methods . 42 3.3 Results . 44 3.4 Discussion . 47 3.5 References . 48 Chapter 4 A Nonlinear Model of Passive Muscle Viscosity . 50 4.1 Introduction . 51 4.2 Methods . 52 4.2.1 Stress relaxation testing . 53 4.2.2 Pseudoplastic model formulation . 54 4.2.3 Model fitting . 57 4.3 Results . 57 4.3.1 Locally linear models . 58 4.3.2 Strain rate sensitivity . 60 4.3.3 Superposition . 64 4.4 Discussion . 68 4.4.1 Muscle as a non-Newtonian material . 70 4.4.2 Sources of passive viscosity . 71 4.5 References . 71 Chapter 5 Skeletal Muscle Fibrosis Develops in Response to Compliant Fibers . 75 5.1 Introduction . 76 5.2 Methods . 77 5.2.1 Ethical approval . 77 5.2.2 Experimental design . 77 5.2.3 Muscle mechanical testing . 78 5.2.4 Microarray processing . 79 5.2.5 Quantitative real-time PCR . 81 5.2.6 Hydroxyproline assay for collagen content . 81 5.2.7 Immunohistochemistry . 82 5.2.8 Flow cytometry . 83 5.2.9 Data processing and statistical analysis . 84 5.3 Results . 84 5.3.1 Altered fiber and bundle material properties . 84 5.3.2 Increased expression of ECM constituients . 87 vii 5.3.3 Altered ECM quantity and quality . 91 5.3.4 Signs of inflammation and regeneration . 93 5.4 Discussion . 98 5.5 Acknowledgements . 101 5.6 References . 102 Chapter 6 Systems Analysis of Genes Related to Skeletal Muscle Function 107 6.1 Abstract . 107 6.2 Introduction . 108 6.3 Neuromuscular junction . 112 6.4 Excitation contraction coupling . 114 6.5 Sarcomere contraction . 116 6.6 Cytoskeleton . 118 6.7 Extracellular matrix . 120 6.8 Energy metabolism . 122 6.9 Inflammation . 125 6.10 Muscle hypertrophy and atrophy . 127 6.11 Muscle fiber type . 129 6.12 Conclusion . 131 6.13 Acknowledgements . 131 6.14 References . 131 Chapter 7 Role of the Cytoskeleton in Muscle Mechanical and Transcrip- tional Responses to Altered Use . 138 7.1 Abstract . 138 7.2 Introduction . 139 7.3 Methods . 140 7.3.1 Eccentric exercise . 141 7.3.2 Microarray processing . 142 7.3.3 Gene classification . 143 7.3.4 Quantitative real-time PCR . 144 7.3.5 Myosin heavy chain isoform determination . 145 7.3.6 Isolated skeletal muscle insulin stimulation . 145 7.3.7 Data processing . 146 7.4 Results . 146 7.4.1 Eccentric contraction induced injury . 146 7.4.2 Gene expression as a function of desmin, age and EC.......................... 148 7.4.3 The effect of desmin deletion on transcriptional EC response . 149 7.4.4 The effect of desmin deletion on the transcrip- tional response to aging . 151 viii 7.4.5 Remodeling, inflammation and fibrosis in des−=− muscle . 153 7.4.6 Fiber type specific expression in des−=− muscle . 154 7.4.7 Peripheral fat accumulation and insulin resistance in des−=− muscle . 156 7.5 Discussion . 158 7.6 Acknowledgements . 161 7.7 References . 162 Chapter 8 Conclusions . 167 8.1 Sarcomere length heterogeneity is restricted by desmin . 168 8.2 The mechanical properties of both fibers and ECM are altered in the absence of desmin . 168 8.3 In the absence of desmin, muscle shows signs of chronic injury . 169 8.4 Desmin deletion alters the muscular response to injury and aging . 169 8.5 Summary . 170 8.6 References . 171 Appendix A Desmin Stiffness Measurement . 172 A.1 References . 175 Appendix B Details of Comparative Models of Linear Viscosity . 176 B.1 Hill models of viscoelasticity . 176 B.2 The quasi-linear viscoelastic theory . 178 B.3 References . 180 Appendix C Supplemental Figures Supporting Fibrosis and Inflammation in Des−=− Muscle . 181 C.1 References . 181 Appendix D Supplemental Figures and Tables Supporting Gene Expression Changes in Des−=− Skeletal Muscle . 188 ix LIST OF FIGURES Figure 1.1: Diagram of muscle macroanatomy . .2 Figure 1.2: Diagram of muscle microanatomy . .4 Figure 1.3: The length-tension and force-velocity relationships . .5 Figure 1.4: Desmin filaments visualized by immunofluorescence and light microscopy . .7 Figure 1.5: Z-disk misalignment in des−=− muscle . .8 Figure 1.6: Biopsies from desmin-related myopathy patients . .9 Figure 2.1: Graphical representation of the finite-element muscle fiber array 19 Figure 2.2: Theoretical passive and active stresses for model components . 22 Figure 2.3: Sarcomere length distributions across the fiber length and initial passive tension . 24 Figure 2.4: Z-disk stagger across the fiber as a function of sarcomere length during passive stretch simulations . 28 Figure 2.5: Length and force traces over time of a representative run for selected sarcomeres . ..