The mechanisms of organ size control remain poorly understood. A key question is how cells collectively sense the overall status of a tissue. We addressed this problem focusing on mouse liver regeneration. Using digital tissue reconstruction and quantitative image analysis, we found that the apical surface of hepatocytes forming the bile canalicular network expands concomitant with an increase in F-actin and phospho-myosin, to compensate an overload of bile acids. These changes are sensed by the Hippo transcriptional co-activator YAP, which localizes to apical F-actin-rich regions and translocates to the nucleus in dependence of the integrity of the actin cytoskeleton. This mechanism tolerates moderate bile acid fluctuations under tissue homeostasis, but activates YAP in response to sustained bile acid overload. Using an integrated biophysical-biochemical model of bile pressure and Hippo signaling, we explained this behavior by the existence of a mechano-sensory mechanism that activates YAP in a switch-like manner. We propose that the apical surface of hepatocytes acts as a self-regulatory mechano-sensory system that responds to critical levels of bile acids as readout of tissue status.
SEEK ID: https://seek.lisym.org/publications/243
PubMed ID: 32090478
Projects: LiSyM Pillar I: Early Metabolic Injury (LiSyM-EMI)
Publication type: Journal
Journal: Mol Syst Biol
Citation: Mol Syst Biol. 2020 Feb;16(2):e8985. doi: 10.15252/msb.20198985.
Date Published: 25th Feb 2020
Registered Mode: by PubMed ID
Views: 1655
Created: 17th Jul 2020 at 07:24
Last updated: 8th Mar 2024 at 07:44
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