Deconstructing Signaling in Three Dimensions

Abstract

Cells in vivo exist within the context of a multicellular tissue, where their behavior is governed by homo- and heterotypic cell–cell interactions, the material properties of the extracellular matrix, and the distribution of various soluble and physical factors. Most methods currently used to study and manipulate cellular behavior in vitro, however, sacrifice physiological relevance for experimental expediency. The fallacy of such approaches has been highlighted by the recent development and application of three-dimensional culture models to cell biology, which has revealed striking phenotypic differences in cell survival, migration, and differentiation in genetically identical cells simply by varying culture conditions. These perplexing findings beg the question of what constitutes a three-dimensional culture and why cells behave so differently in two- and three-dimensional culture formats. In the following review, we dissect the fundamental differences between two- and three-dimensional culture conditions. We begin by establishing a basic definition of what “three dimensions” means at different biological scales and discuss how dimensionality influences cell signaling across different length scales. We identify which three-dimensional features most potently influence intracellular signaling and distinguish between conserved biological principles that are maintained across culture conditions and cellular behaviors that are sensitive to microenvironmental context. Finally, we highlight state-of-the-art molecular tools amenable to the study of signaling in three dimensions under conditions that facilitate deconstruction of signaling in a more physiologically relevant manner.

Measuring Cell Viscoelastic Properties Using a Microfluidic Extensional Flow Device

“…Although it has been long understood that soluble factors from the cellular microenvironment can strongly influence cellular behavior, it is becoming increasingly clear that physical, and especially mechanical, inputs can also affect cell behaviors such as migration, proliferation, and differentiation (1)(2)(3)(4). Cells frequently respond to mechanical stimuli by adaptively tuning their intrinsic mechanical properties, and significant evidence suggests that this ''mechanoadaptation'' is key to transducing these inputs into biochemical signals that mediate cell behavior.…”

Enzymatically degradable poly(ethylene glycol) hydrogels for the 3D culture and release of human embryonic stem cell derived pancreatic precursor cell aggregates

“…The dimensionality of culture platforms is increasingly being recognized as an important factor for the in vitro culture of cells [1–3]. In three dimensional (3D) culture, cells are often embedded within a material where they can migrate and experience cell-matrix interactions and cell-cell contacts in all directions.…”

Physical view on migration modes

“…The stability and physiological importance of cell-matrix adhesions seem to be strongly reduced in high speed-migrating amoeboid cells such as immune cells, which are able to migrate in the blebbing mode and in the protrusive mode (Lämmermann and Sixt, 2009;Fackler and Grosse, 2008). Moreover, the dimensionality of the microenvironment is suggested to have a broad impact on the motility efficiency and the migration speed of cells (Rubashkin et al, 2014;Mierke et al, 2010). In addition, there is evidence that these two migration modes occur on 2-D and in 3-D microenvironments in a similar manner.…”