Detection of Dynamic Spatiotemporal Response to Periodic Chemical Stimulation in a Xenopus Embryonic Tissue

Abstract

Embryonic development is guided by a complex and integrated set of stimuli that results in collective system-wide organization that is both time and space regulated. These regulatory interactions result in the emergence of highly functional units, which are correlated to frequency-modulated stimulation profiles. We have determined the dynamic response of vertebrate embryonic tissues to highly controlled, time-varying localized chemical stimulation using a microfluidic system with feedback control. Our approach has enabled localized spatiotemporal manipulation of the steroid hormone dexamethasone (DEX) in Animal Cap (AC) tissues isolated from gastrulating Xenopus embryos. Using this approach we investigated cell-scale responses to precisely controlled stimulation by tracking the redistribution of a GFP-tagged DEX-reporter constructed from the human glucocorticoid receptor (GR). We exposed defined regions of a single AC explant to different stimulation conditions—continuous stimulation, periodic stimulation, and no stimulation. We observed collective behavior of the GR transport into the nucleus was first-order. Furthermore, the dynamic response was well-modeled by a first-order differential equation with a single time derivative. The model predicted that responses to periodic stimulations closely matched the results of the frequency-based experiments. We find that stimulation with localized bursts versus continuous stimulation can result in highly distinct responses. This finding is critical as controlled space and time exposure to growth factors is a hallmark of complex processes in embryonic development. These complex responses to cellular signaling and transport machinery were similar to emergent behaviors in other complex systems, suggesting that even within a complex embryonic tissue, the overall system can converge toward a predictive first-order response.

Transport of Dynamic Biochemical Signals in Steady Flow in a Shallow Y-Shaped Microfluidic Channel: Effect of Transverse Diffusion and Longitudinal Dispersion

“…In recent years, the interactions between cells and extracellular microenvironments have received more attention in the field of cell biology [4][5][6][7][8]. Researches show that cells in response to dynamic signals exhibit different characteristics from those to static ones [9][10][11][12][13][14]. However, while most of the previous investigations focused on the cellular behaviors in response to static biomechanical and/or biochemical signals [9][10][11], few studied the effect of dynamic signals [12][13][14].…”

“…Researches show that cells in response to dynamic signals exhibit different characteristics from those to static ones [9][10][11][12][13][14]. However, while most of the previous investigations focused on the cellular behaviors in response to static biomechanical and/or biochemical signals [9][10][11], few studied the effect of dynamic signals [12][13][14]. Thus, a controlled quantitative loading of dynamic biomechanical and biochemical signals on cells cultured in vitro is needed to provide more insights into the biological processes and behaviors of the cells.…”

“…To date, microfiuidics has become a popular and effective experimental platform to study the interactions between cells and their microenvironments [10,11,[13][14][15][16][17][18][19][20][21][22][23]. Many types of microfiuidic devices have been developed to generate biomechanical and biochemical signals for specific cellular biological applications.…”

Nanomedicines for endothelial disorders

“…This integrative approach can be applied to optimize nanoparticles and study their potentials in a range of other diseases, including cancer, diabetes, and inflammation. In the future, the ability to create physiologically realistic microsystems that can mimic in vitro microvessels [225, 226], and manipulate in vivo small organisms [227] or ex vivo embryonic tissue excised from live embryos [228–231], will allow the identification and prediction of the potential of nanomedicines and pave the path for their rapid clinical translation.…”

3D bio-etching of a complex composite-like embryonic tissue

“…Microfluidics offer high molecular selectivity and micron scale spatial accuracy to spatially control sub-cellular processes; a level of control that is extremely challenging without laminar flow, since small molecules diffuse across the distance of a cell diameter within seconds 11 . Spatiotemporal control offered by microfluidics allows long-term studies of localized responses of cells and tissues to chemical stimuli, which are critical in numerous areas including developmental biology and biological materials 6,11,12 .…”