A systems analysis of liver regeneration
During development and regeneration, organs must attain proper shape and size. This requires a control system that coordinates the behavior of individual cells to ensure correct structure and function of the tissue. How cells sense the overall tissue status and size, remains a largely unexplored question.
Researchers at the Max Planck Institute of Molecular Cell Biology and Genetics in Dresden (MPI-CBG) and the TU Dresden studied the regeneration of the liver in the mouse and discovered a novel control mechanism whereby changes in cell structure, caused by metabolic overload, inform cells about the integrity of the whole organ through a mechano-sensory mechanism. The study is published in the journal Molecular Systems Biology.
The liver has the unique capacity to regenerate. Following tissue injury, the organ restores the original tissue mass within just a few days. Previous work in the field emphasized the importance of metabolism for liver regeneration. However, it is still poorly understood, how the organ orchestrates the regenerative response throughout scales of organization to ensure the restoration of the original mass.
To address this problem, the research team around MPI-CBG director Marino Zerial together with colleagues from the Center for Information Services and High Performance Computing (ZIH) at the TU Dresden, studied liver regeneration in the mouse.
The scientists digitally reconstructed liver tissue using high‐resolution microscopy and quantitative 3D image analysis to explore tissue and cellular changes during liver regeneration. Following liver resection, the remaining tissue experiences a metabolic overload of bile acids due to the recirculation of bile acids in the body.
Such overload induces an expansion of the bile canalicular network, a system of little tubings made by the liver cells (hepatocytes) to produce and distribute the bile that helps the digestion in the intestine. Remarkably, the bile canaliculi network, which is built by the plasma membrane of individual hepatocytes, senses the overload of bile acids and relays the information to the cells to induce a regenerative response.
Kirstin Meyer, the first author of the study, explains: “This simple mechanism relays tissue level information on liver function to individual cells through the mechano-sensory function of the Hippo signaling pathway.” Bile acid levels are known to change not only during liver regeneration, but also in response to other environmental stimuli, such as diet and circadian rhythm. Why do these changes not induce a regenerative response?
Lutz Brusch (ZIH) states: “We developed a biophysical-biochemical model of bile pressure and Hippo signaling. This model suggests a mechanism that activates YAP, the effector of the Hippo pathway, in a switch-like manner.” Kirstin Meyer continues: “The threshold for activation is not reached by moderate bile acid fluctuations, but only upon severe perturbations such as tissue resection. We suggest that the bile canaliculi network acts as a self‐regulatory system that responds to critical levels of bile acids to induces the regeneration process of the liver.”
How organs control growth and regenerate, are important biomedical questions. New insights may provide both a better understanding of abnormal growth conditions, such as cancer, and new avenues for regenerative therapies. Marino Zerial, who oversaw the study summarizes: “Our findings connect previous knowledge on the importance of bile acid metabolism for liver regeneration with the cell biology of liver cells and the organization of cells into tissues, paving the way towards a systems understanding of how cells sense instructive signals in liver regeneration.”
About the MPI-CBG
The Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG) is one of over 80 institutes of the Max Planck Society, an independent, non-profit organization in Germany. 600 curiosity-driven scientists from over 50 countries ask: How do cells form tissues? The basic research programs of the MPI-CBG span multiple scales of magnitude, from molecular assemblies to organelles, cells, tissues, organs, and organisms.
About the ZIH
The Center for Information Services and High Performance Computing (ZIH) at Technische Universität Dresden is the central provider of supercomputing resources in the free state of Saxony. ZIH provides free access to its HPC systems including ca. 47.000 compute cores for members of universities and research institutes across Germany as well as beyond. The main focus of ZIH's research agenda is the promotion of scientific and data-intensive computing from algorithm development and machine learning (AI) to the optimisation of simulation and analysis workflows. For the life sciences, researchers at ZIH are modeling the dynamic processes in cells and tissues using ZIH's unique open source software framework Morpheus and tightly integrating quantitative biomedical data.
Prof. Marino Zerial
+49 (0) 351 210 1100
Kirstin Meyer, Hernan Morales‐Navarrete, Sarah Seifert, Michaela Wilsch‐Braeuninger, Uta Dahmen, Elly M Tanaka, Lutz Brusch, Yannis Kalaidzidis, Marino Zerial: “Bile canaliculi remodeling activates YAP via the actin cytoskeleton during liver regeneration” Molecular Systems Biology, 24. February 2020. Doi: 10.15252/msb.20198985
Katrin Boes | Max-Planck-Institut für molekulare Zellbiologie und Genetik
First SARS-CoV-2 genomes in Austria openly available
03.04.2020 | CeMM Forschungszentrum für Molekulare Medizin der Österreichischen Akademie der Wissenschaften
Do urban fish exhibit impaired sleep? Light pollution suppresses melatonin production in European perch
03.04.2020 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)
Drops of water falling on or sliding over surfaces may leave behind traces of electrical charge, causing the drops to charge themselves. Scientists at the Max Planck Institute for Polymer Research (MPI-P) in Mainz have now begun a detailed investigation into this phenomenon that accompanies us in every-day life. They developed a method to quantify the charge generation and additionally created a theoretical model to aid understanding. According to the scientists, the observed effect could be a source of generated power and an important building block for understanding frictional electricity.
Water drops sliding over non-conducting surfaces can be found everywhere in our lives: From the dripping of a coffee machine, to a rinse in the shower, to an...
90 million-year-old forest soil provides unexpected evidence for exceptionally warm climate near the South Pole in the Cretaceous
An international team of researchers led by geoscientists from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) have now...
The bacteria that cause tuberculosis need iron to survive. Researchers at the University of Zurich have now solved the first detailed structure of the transport protein responsible for the iron supply. When the iron transport into the bacteria is inhibited, the pathogen can no longer grow. This opens novel ways to develop targeted tuberculosis drugs.
One of the most devastating pathogens that lives inside human cells is Mycobacterium tuberculosis, the bacillus that causes tuberculosis. According to the...
An international team with the participation of Prof. Dr. Michael Kues from the Cluster of Excellence PhoenixD at Leibniz University Hannover has developed a new method for generating quantum-entangled photons in a spectral range of light that was previously inaccessible. The discovery can make the encryption of satellite-based communications much more secure in the future.
A 15-member research team from the UK, Germany and Japan has developed a new method for generating and detecting quantum-entangled photons at a wavelength of...
Together with their colleagues from the University of Würzburg, physicists from the group of Professor Alexander Szameit at the University of Rostock have devised a “funnel” for photons. Their discovery was recently published in the renowned journal Science and holds great promise for novel ultra-sensitive detectors as well as innovative applications in telecommunications and information processing.
The quantum-optical properties of light and its interaction with matter has fascinated the Rostock professor Alexander Szameit since College.
02.04.2020 | Event News
26.03.2020 | Event News
23.03.2020 | Event News
03.04.2020 | Materials Sciences
03.04.2020 | Life Sciences
03.04.2020 | Life Sciences