A dynamically diluted alignment model reveals the impact of cell turnover on the plasticity of tissue polarity patterns

Hoffmann, Karl B.; Voß-Böhme, Anja; Rink, Jochen C.; Brusch, Lutz

doi:10.1098/rsif.2017.0466

Cited by 7 publications

(3 citation statements)

References 66 publications

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“…Further, another similarity between these two systems is in terms of the external cues, that is external magnetic field in case of ferromagnetic XY model [59] and the tissue level expression gradients in case of PCP. It needs to be pointed out though that these parallels between statistical mechanics models of magnetization and PCP have also been suggested previously [37, 60, 39].…”

Section: Discussionsupporting

confidence: 67%

Continuum Theory for Planar Cell Polarity

Rizvi

Singh

Jolly

2021

Preprint

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Planar Cell Polarity (PCP), characterized by asymmetric localization of proteins at the cell membrane within the epithelial plane, plays essential roles in embryonic development and physiological functions. The significance of PCP can be appreciated by the outcomes of its failure in the form of defects in neural tube formation, tracheal malfunctions, organ shape misregulation, hair follicle misalignment etc. Extensive experimental works on PCP in fruit fly Drosophila melanogaster have classified the proteins involved in PCP into a ‘core’ module, acting locally by inter-cellular protein interactions, and a ‘global’ module, responsible for the alignment of cell polarities with that of the tissue axis. Despite the involvement of different molecular players the asymmetric localization of the proteins of the two modules on cell membrane primarily involves inter-cellular dimer formations. We have developed a continuum model of the localization of PCP proteins on the cell membrane and its regulation via intra- and inter-cellular protein-protein interactions. We have identified the conditions for the asymmetric protein localization, or PCP establishment, for uniform and graded protein expression levels in the tissue. We have found that in the absence of any tissue level expression gradient polarized state of the tissue does not arise. However, in the presence of tissue-level expression gradients of proteins the polarized state remains stable. We have also looked at the influence of the loss of PCP proteins from a select region of the tissue on the polarization of the cells outside of that region. This continuum theory of planar cell polarity can be coupled with active-matter hydrodynamics to study cell flows and their regulation by genetic machinery.

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Section: Discussionsupporting

confidence: 67%

Continuum Theory for Planar Cell Polarity

Rizvi

Singh

Jolly

2021

Preprint

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“…From a methodological perspective, the deeper understanding of physiological behavior was obtained by the close integration of numerical and analytical methods as opposed to just applying numerical simulations alone. This integrated approach has been fruitfully applied before to questions of signaling, spatio-temporal patterning and function in liver cells 32 , pancreas 33 and tissue regeneration 34 .…”

Section: Discussionmentioning

confidence: 99%

Wet-tip versus dry-tip regimes of osmotically driven fluid flow

Ostrenko

Hampe

Brusch

2019

Sci Rep

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The secretion of osmolytes into a lumen and thereby caused osmotic water inflow can drive fluid flows in organs without a mechanical pump. Such fluids include saliva, sweat, pancreatic juice and bile. The effects of elevated fluid pressure and the associated mechanical limitations of organ function remain largely unknown since fluid pressure is difficult to measure inside tiny secretory channels in vivo. We consider the pressure profile of the coupled osmolyte-flow problem in a secretory channel with a closed tip and an open outlet. Importantly, the entire lateral boundary acts as a dynamic fluid source, the strength of which self-organizes through feedback from the emergent pressure solution itself. We derive analytical solutions and compare them to numerical simulations of the problem in three-dimensional space. The theoretical results reveal a phase boundary in a four-dimensional parameter space separating the commonly considered regime with steady flow all along the channel, here termed “wet-tip” regime, from a “dry-tip” regime suffering ceased flow downstream from the closed tip. We propose a relation between the predicted phase boundary and the onset of cholestasis, a pathological liver condition with reduced bile outflow. The phase boundary also sets an intrinsic length scale for the channel which could act as a length sensor during organ growth.

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“…Not only are the observed dynamics qualitatively consistent with the central assumptions of our model (Figure 7), but the model also provides a nontrivial rationale for the observed gradual slow down of the repolarization front ( Figure 4I). This effect arises from our implementation of polarity propagation via a nondirectional diffusion term that we previously showed to emerge from the discrete coupling of each cell's polarity vector toward the average of its neighbors (Hoffmann et al, 2017;Merkel et al, 2014). Consequently, the influence of the boundary state weakens as a function of distance from the ectopic head tip and the repolarization front halts once the local influence of both heads is equal, i.e., at the geometric midpoint of doubleheaded animals ( Figure 3B).…”

Section: Polarity Dynamicsmentioning

confidence: 99%