scholarly journals Contact inhibition of locomotion and mechanical cross-talk between cell–cell and cell–substrate adhesion determine the pattern of junctional tension in epithelial cell aggregates

2016 ◽  
Vol 27 (22) ◽  
pp. 3436-3448 ◽  
Author(s):  
Luke Coburn ◽  
Hender Lopez ◽  
Benjamin J. Caldwell ◽  
Elliott Moussa ◽  
Chloe Yap ◽  
...  

We used a computational approach to analyze the biomechanics of epithelial cell aggregates—islands, stripes, or entire monolayers—that combines both vertex and contact-inhibition-of-locomotion models to include cell–cell and cell–substrate adhesion. Examination of the distribution of cell protrusions (adhesion to the substrate) in the model predicted high-order profiles of cell organization that agree with those previously seen experimentally. Cells acquired an asymmetric distribution of basal protrusions, traction forces, and apical aspect ratios that decreased when moving from the edge to the island center. Our in silico analysis also showed that tension on cell–cell junctions and apical stress is not homogeneous across the island. Instead, these parameters are higher at the island center and scale up with island size, which we confirmed experimentally using laser ablation assays and immunofluorescence. Without formally being a three-dimensional model, our approach has the minimal elements necessary to reproduce the distribution of cellular forces and mechanical cross-talk, as well as the distribution of principal stress in cells within epithelial cell aggregates. By making experimentally testable predictions, our approach can aid in mechanical analysis of epithelial tissues, especially when local changes in cell–cell and/or cell–substrate adhesion drive collective cell behavior.

2013 ◽  
Vol 127 (4) ◽  
pp. 885-895 ◽  
Author(s):  
Christina M. Van Itallie ◽  
Amber Jean Tietgens ◽  
Angel Aponte ◽  
Karin Fredriksson ◽  
Alan S. Fanning ◽  
...  

2020 ◽  
Vol 319 (2) ◽  
pp. L369-L379
Author(s):  
Daniel D. Lee ◽  
Alexandra Hochstetler ◽  
Eric Sah ◽  
Haiming Xu ◽  
Chinn-Woan Lowe ◽  
...  

Proper development of the respiratory bronchiole and alveolar epithelium proceeds through coordinated cross talk between the interface of epithelium and neighboring mesenchyme. Signals that facilitate and coordinate the cross talk as the bronchial forming canalicular stage transitions to construction of air-exchanging capillary-alveoli niche in the alveolar stage are poorly understood. Expressed within this decisive region, levels of aminoacyl-tRNA synthetase complex-interacting multifunctional protein 1 (AIMP1) inversely correlate with the maturation of the lung. The present study addresses the role of AIMP1 in lung development through the generation and characterization of Aimp1−/− mutant mice. Mating of Aimp1+/− produced offspring in expected Mendelian ratios throughout embryonic development. However, newborn Aimp1−/− pups exhibited neonatal lethality with mild cyanosis. Imaging both structure and ultrastructure of Aimp1−/− lungs showed disorganized bronchial epithelium, decreased type I but not type II cell differentiation, increased distal vessels, and disruption of E-cadherin deposition in cell-cell junctions. Supporting the in vivo findings of disrupted epithelial cell-cell junctions, in vitro biochemical experiments show that a portion of AIMP1 binds to phosphoinositides, the lipid anchor of proteins that have a fundamental role in both cellular membrane and actin cytoskeleton organization; a dramatic disruption in F-actin cytoskeleton was observed in Aimp1−/− mouse embryonic fibroblasts. Such observed structural defects may lead to disrupted cell-cell boundaries. Together, these results suggest a requirement of AIMP1 in epithelial cell differentiation in proper lung development.


2014 ◽  
Vol 11 (100) ◽  
pp. 20140684 ◽  
Author(s):  
Chenlu Wang ◽  
Sagar Chowdhury ◽  
Meghan Driscoll ◽  
Carole A. Parent ◽  
S. K. Gupta ◽  
...  

Collective cell migration often involves notable cell–cell and cell–substrate adhesions and highly coordinated motion of touching cells. We focus on the interplay between cell–substrate adhesion and cell–cell adhesion. We show that the loss of cell-surface contact does not significantly alter the dynamic pattern of protrusions and retractions of fast migrating amoeboid cells ( Dictyostelium discoideum ), but significantly changes their ability to adhere to other cells. Analysis of the dynamics of cell shapes reveals that cells that are adherent to a surface may coordinate their motion with neighbouring cells through protrusion waves that travel across cell–cell contacts. However, while shape waves exist if cells are detached from surfaces, they do not couple cell to cell. In addition, our investigation of actin polymerization indicates that loss of cell-surface adhesion changes actin polymerization at cell–cell contacts. To further investigate cell–cell/cell–substrate interactions, we used optical micromanipulation to form cell–substrate contact at controlled locations. We find that both cell-shape dynamics and cytoskeletal activity respond rapidly to the formation of cell–substrate contact.


Pathology ◽  
1992 ◽  
Vol 24 ◽  
pp. 26
Author(s):  
M.A. Vadas ◽  
J.R. Gamble ◽  
Y. Khew-Goodall ◽  
P. Kaur

1995 ◽  
Vol 108 (2) ◽  
pp. 831-838 ◽  
Author(s):  
B.E. Symington ◽  
W.G. Carter

We previously reported that integrin alpha 3 beta 1 mediates epidermal intercellular adhesion as well as cell-substrate adhesion. P1B5, an anti-alpha 3 beta 1 specific monoclonal antibody, is a potent in vitro trigger of epidermal cell-cell adhesion and an inhibitor of cell-substrate adhesion. We now show that P1B5 specifically induces the intercellular localization of integrins alpha 2 beta 1 and alpha 3 beta 1, consistent with its role in inducing intercellular adhesion via these two integrins. P1F2, another anti-alpha 3 beta 1 antibody, does not induce either intercellular adhesion or intercellular accumulation of alpha 3 beta 1 and alpha 2 beta 1. Growth of epidermal cells in high calcium, known to induce epidermal differentiation, also induces intercellular accumulation of alpha 3 beta 1 and alpha 2 beta 1 and increased cell-cell adhesion. We therefore asked whether P1B5 treatment induces epidermal differentiation. P1B5 treatment induces changes consistent with epidermal differentiation, including increased involucrin expression, stratification, and production of squames. P1F2 treatment has none of these effects. In vivo, epidermal basal cells are in close contact with the epithelial basement membrane component epiligrin. Growth of keratinocytes on purified epiligrin but not other matrix components specifically reduces involucrin expression by P1B5-treated keratinocytes. These results suggest that integrin alpha 3 beta 1 has a unique role in epidermal differentiation, that the epitope recognized by P1B5 is involved in triggering this differentiation, and that keratinocyte adhesion to epiligrin inhibits alpha 3 beta 1-mediated differentiation.(ABSTRACT TRUNCATED AT 250 WORDS)


2014 ◽  
Vol 25 (12) ◽  
pp. 1854-1866 ◽  
Author(s):  
Andrea Aguilar ◽  
Lars Becker ◽  
Thomas Tedeschi ◽  
Stefan Heller ◽  
Carlo Iomini ◽  
...  

Acetylation of α-tubulin on lysine 40 marks long-lived microtubules in structures such as axons and cilia, and yet the physiological role of α-tubulin K40 acetylation is elusive. Although genetic ablation of the α-tubulin K40 acetyltransferase αTat1 in mice did not lead to detectable phenotypes in the developing animals, contact inhibition of proliferation and cell–substrate adhesion were significantly compromised in cultured αTat1−/− fibroblasts. First, αTat1−/− fibroblasts kept proliferating beyond the confluent monolayer stage. Congruently, αTat1−/− cells failed to activate Hippo signaling in response to increased cell density, and the microtubule association of the Hippo regulator Merlin was disrupted. Second, αTat1−/− cells contained very few focal adhesions, and their ability to adhere to growth surfaces was greatly impaired. Whereas the catalytic activity of αTAT1 was dispensable for monolayer formation, it was necessary for cell adhesion and restrained cell proliferation and activation of the Hippo pathway at elevated cell density. Because α-tubulin K40 acetylation is largely eliminated by deletion of αTAT1, we propose that acetylated microtubules regulate contact inhibition of proliferation through the Hippo pathway.


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