Book Description

Cell-microenvironment interactions are essential to tissue and organ functions and to overall health, but studying these dynamic and bidirectional relationships in vivo is typically not practical or results are difficult to interpret. in vitro models with improved accessibility, increased tractability, and more numerous available readouts have been widely utilized and promise to continue to provide valuable insights into regulation between cells and their microenvironments. However, there remain aspects of in vitro model interrogation and design that are suboptimal. This document presents new approaches for connecting cells to their location at a sub-model level, for investigating the effects of model parameters on populations, and for generating a model with a desired global structure. Thereby the work presented here has implications for the way in vitro models are used and designed on three levels of model structure. First, though there exists heterogeneity in cells and in microenvironments and though these differences influence each other, existing techniques limitedly enable characterization of cells while maintaining contextual information. The method in Chapter 2 allows one to impart position dependent signals to cells on a substrate in a straightforward and customizable fashion. The method will be applicable in tracking cells before and after dissociation as well as in defining soluble factor patterning. Second, in vitro models are increasingly complex, however there is little systematic knowledge concerning how complexity affects cellular behaviors and model function. Chapters 3 and 4 describe effects of 3D matrix composition and heterotypic complexity. These studies use models that allow single parameter changes to dissect the impact of a variable. Integration of these results with other similarly systematic studies with implementation of data analysis techniques has the potential to guide model design and demonstrate fundamental aspects of cell-microenvironment interactions. Finally, in chapter 5 design considerations for a microscale in vitro model that recreates many structural and functional attributes of in vivo skin are presented. Modes of failure associated with translation to the microscale as well as solutions that invoke physical phenomena at the microscale are discussed. The model itself and the design features implemented promise to be useful tools moving forward.