BRITE Relaunch: Using Cell Shape and Cytoskeletal Organization for Understanding and Predicting Cellular Force Generation

Colorado State University, Fort Collins CO

Investigators

Abstract

Cells use pulling, or contractile, forces for many important physiological processes. These contractile forces drive cell division and cell migration. Cells of the immune system, as well as invaders like metastatic cancer cells, use these forces to squeeze through tissue and even deform their own nuclei to slip through tiny spaces. Methods to directly measure these forces have been developed, but they are expensive, challenging, and have limitations. This Boosting Research Ideas for Transformative and Equitable Advances in Engineering (BRITE) Relaunch project aims to develop imaging-based methods to estimate cellular forces easier and cheaper than currently possible. The methods promise to make these mechanical forces shaping healthy or diseased tissues more easily measurable through the theoretical and experimental techniques to be employed. Graduate students and undergraduate students will be trained in this research. Additionally, new course material will be developed for traditional engineering courses to enable students to develop an understanding of real-world problems and societal goals. Simulations will also be developed as an aid to learning science for high school, middle school, and college students. This project will uncover the relationship between cellular contractile forces and the organization of the filamentous actin structure and will develop tools for predictive mapping of forces from actin organization. Contractile forces are exerted by the cellular cytoskeleton, and previous work has led to the hypothesis that measuring cytoskeletal organization visible in fluorescence microscopy images may allow for the prediction of these forces. This overarching hypothesis will be tested using computer simulations, experiments, imaging and artificial intelligence methods. The actin cytoskeleton will be simulated using specialized cytoskeletal simulation software. By changing parameters and initial conditions, many types of cytoskeletal structures will be generated, and forces exerted by motor proteins on focal adhesions will be measured. The relation between cytoskeletal organization and force distribution will be investigated using machine learning methods. Cells will be cultured and plated on glass surfaces and imaged using live- or fixed- cell actin and DNA stains. Cytoskeletal structure with and without genetic perturbations will be imaged, and differences in architecture identified and contrasted with simulation predictions. Forces exerted by the cells on focal adhesions will be measured and the cytoskeletal structure in these cells will be simultaneously imaged. Machine learning and high-dimensional data analysis methods will be applied to understand the relation between forces and cytoskeletal organization. Experimental results will provide feedback and improved simulations. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.