The Effects of Membrane and Cytoskeletal Mechanics on Cell Adhesiveness


Book Description

The cytoskeleton, the internal network of filaments that regulates cell shape and structure, has been implicated in several critical aspects of cell adhesion. Its role, however, has primarily been demonstrated as a component of the numerous intracellular signaling events that regulate cell surface receptors. In this study we sought to gain insight into how the mechanical properties of the cytoskeleton could affect adhesion. Specifically, we addressed how membrane deformability, which we demonstrate is critically dependent upon tethering to the cytoskeleton, could impact a whole cell adhesion assay. To modify membrane deformability, we treated cells with the pharmacological agents phalloidin, Latrinculin B, Cytochalasin D, colchicine, and Paclitaxel, which have varying effects on microfilaments and microtubules, two of the main constituents of the cytoskeleton. We found that dissolution of the actin cytoskeleton could reduce the number of adherent cells to a callogen-coated substrate by over 85%. We theorize that this is due largely to the inhibition of signaling events associated with the cytoskeleton, but it may also be affected by changes in shape and deformability. To truly understand the implications of this experiment, we believe further study using high-resolution force technology such as atomic force microscopy or magnetic bead microrheometry is necessary.










Cell and Matrix Mechanics


Book Description

Explores a Range of Multiscale Biomechanics/Mechanobiology Concepts Cell and Matrix Mechanics presents cutting-edge research at the molecular, cellular, and tissue levels in the field of cell mechanics. This book involves key experts in the field, and covers crucial areas of cell and tissue mechanics, with an emphasis on the roles of mechanical forces in cell–matrix interactions. Providing material in each chapter that builds on the previous chapters, it effectively integrates length scales and contains, for each length scale, key experimental observations and corresponding quantitative theoretical models. Summarizes the Three Hierarchical Levels of Cell Mechanics The book contains 14 chapters and is organized into three sections. The first section focuses on the molecular level, the second section details mechanics at the cellular level, and the third section explores cellular mechanics at the tissue level. The authors offer a thorough description of the roles of mechanical forces in cell and tissue biology, and include specific examples. They incorporate descriptions of associated theoretical models, and provide the data and modeling framework needed for a multi-scale analysis. In addition, they highlight the pioneering studies in cell–matrix mechanics by Albert K. Harris. The topics covered include: The passive and active mechanical properties of cytoskeletal polymers and associated motor proteins along with the behavior of polymer networks The mechanical properties of the cell membrane, with an emphasis on membrane protein activation caused by membrane forces The hierarchical organization of collagen fibrils, revealing that a delicate balance exists between specific and nonspecific interactions to result in a structure with semicrystalline order as well as loose associations The roles of matrix mechanical properties on cell adhesion and function along with different mechanical mechanisms of cell–cell interactions The effects of mechanical loading on cell cytoskeletal remodeling, summarizing various modeling approaches that explain possible mechanisms regulating the alignment of actin stress fibers in response to stretching The mechanical testing of cell-populated collagen matrices, along with theory relating the passive and active mechanical properties of the engineered tissues Cell migration behavior in 3-D matrices and in collective cell motility The role of mechanics in cartilage development The roles of both cellular and external forces on tissue morphogenesis The roles of mechanical forces on tumor growth and cancer metastasis Cell and Matrix Mechanics succinctly and systematically explains the roles of mechanical forces in cell–matrix biology. Practitioners and researchers in engineering and physics, as well as graduate students in biomedical engineering and mechanical engineering related to mechanobiology, can benefit from this work.







Cytomechanics


Book Description

Genetic information determines the composition of molecules comprising cytoskeletal elements, membranes and receptors. The supramolecular arrangement of these components represents a self-assembly process controlled by physicochemical and mechanical interactions. This general hypothesis demarcates the aim of studying cellular mechanics. Description and evaluation of mechanical properties of cells and their organelles, as well as of the forces exerted by them, is the scope of this book on Cytomechanics. Emphasis is laid on the role of mechanical properties in the generation of shape and cytoplasmic motion, and on the basic principles and components determining mechanical properties.







Cell Mechanics and Cellular Engineering


Book Description

Cell mechanics and cellular engineering may be defined as the application of principles and methods of engineering and life sciences toward fundamental understanding of structure-function relationships in normal and pathological cells and the development of biological substitutes to restore cellular functions. This definition is derived from one developed for tissue engineering at a 1988 NSF workshop. The reader of this volume will see the definition being applied and stretched to study cell and tissue structure-function relationships. The best way to define a field is really to let the investigators describe their areas of study. Perhaps cell mechanics could be compartmentalized by remembering how some of the earliest thinkers wrote about the effects of mechanics on growth. As early as 1638, Galileo hypothesized that gravity and of living mechanical forces place limits on the growth and architecture organisms. It seems only fitting that Robert Hooke, who gave us Hooke's law of elasticity, also gave us the word "cell" in his 1665 text, Micrographid, to designate these elementary entities of life. Julius Wolffs 1899 treatise on the function and form of the trabecular architecture provided an incisive example of the relationship between the structure of the body and the mechanical load it bears. In 1917, D' Arcy Thompson's On Growth and Form revolutionized the analysis of biological processes by introducing cogent physical explanations of the relationships between the structure and function of cells and organisms.




Cellular and Biomolecular Mechanics and Mechanobiology


Book Description

This book describes these exciting new developments, and presents experimental and computational findings that altogether describe the frontier of knowledge in cellular and biomolecular mechanics, and the biological implications, in health and disease. The book is written for bioengineers with interest in cellular mechanics, for biophysicists, biochemists, medical researchers and all other professionals with interest in how cells produce and respond to mechanical loads.




Structure and Dynamics of Membranes


Book Description

The first volume of the Handbook deals with the amazing world of biomembranes and lipid bilayers. Part A describes all aspects related to the morphology of these membranes, beginning with the complex architecture of biomembranes, continues with a description of the bizarre morphology of lipid bilayers and concludes with technological applications of these membranes. The first two chapters deal with biomembranes, providing an introduction to the membranes of eucaryotes and a description of the evolution of membranes. The following chapters are concerned with different aspects of lipids including the physical properties of model membranes composed of lipid-protein mixtures, lateralphase separation of lipids and proteins and measurement of lipid-protein bilayer diffusion. Other chapters deal with the flexibility of fluid bilayers, the closure of bilayers into vesicles which attain a large variety of different shapes, and applications of lipid vesicles and liposomes. Part B covers membrane adhesion, membrane fusion and the interaction of biomembranes withpolymer networks such as the cytoskeleton. The first two chapters of this part discuss the generic interactions of membranes from the conceptual point of view. The following two chapters summarize the experimental work on two different bilayer systems. The next chapter deals with the process ofcontact formation, focal bounding and macroscopic contacts between cells. The cytoskeleton within eucaryotic cells consists of a network of relatively stiff filaments of which three different types of filaments have been identified. As explained in the next chapter much has been recently learned aboutthe interaction of these filaments with the cell membrane. The final two chapters deal with membrane fusion.