La contraction musculaire en quatre échelles

Habilitation à Diriger les Recherches

Preface

This website is the HTML version of Dr. Matthieu Caruel Research Habilitation (habilitation à diriger les recherches).

Muscle contraction orginates from the enzymatic activity of nanoscale ATPase molecular motors that convert the metabolic energy provided by the ATP hydrolysis into mechanical work. Their coordinated action generates the observable deformation of the muscle tissue at the macroscale. This concerted nano-to-macro force transmission is achieved thanks to the highly hierarchical internal structure of the tissue, that organizes and regulates the contraction at various scales.

The purpose of this document is to provide an overview of Matthieu Caruel’s contribution to the research on muscle contraction at these several scales.

In Chapter 1, we start by giving the essential background on muscle contraction necessary to understand the positioning of our research and its goals. A macroscopic model of the muscle tissue is presented in Chapter 2, with an emphasis on the formulation of reduced models based on simplified geometries for modeling a muscle fiber and a cardiac ventricle. The force generation process by molecular motors is described in Chapter 3, where we present the classical chemical-mechanical approach and the hybrid jump-diffusion approach proposed by M. Caruel and colleagues. At the microscale, molecular motors operate in small groups called contractile units. Chapter 4 is dedicated to the modeling of the mechanical coupling of the molecular motors at this scale and its consequences on the force production. The structures connecting contractiles units to form muscle fibers within the tissue are introduced in Chapter 5. This chapter addresses the question of the mechanical pathways involved in the regulation of muscle contraction.

All chapters are organized similarly. We start by an introduction providing the technical background and presenting the research challenges, before summarizing M. Caruel’s contributions with references to the corresponding publications. A list of perspectives is established at the end of each chapter. Chapter 6 recapitulates these perspectives and briefly discuss potential applications of our work.