scholarly journals Tracking Epithelial Cell Junctions in C. elegans Embryogenesis With Active Contours Guided by SIFT Flow

2015 ◽  
Vol 62 (4) ◽  
pp. 1020-1033 ◽  
Author(s):  
Sukryool Kang ◽  
Chen-Yu Lee ◽  
Monira Goncalves ◽  
Andrew D. Chisholm ◽  
Pamela C. Cosman
Keyword(s):  
Epithelial Cell ◽  
Active Contours ◽  
Cell Junctions ◽  
C Elegans ◽  
Sift Flow

scholarly journals Influence of aminoacyl-tRNA synthetase complex-interacting multifunctional protein 1 on epithelial differentiation and organization during lung development

2020 ◽  
Vol 319 (2) ◽  
pp. L369-L379
Author(s):  
Daniel D. Lee ◽  
Alexandra Hochstetler ◽  
Eric Sah ◽  
Haiming Xu ◽  
Chinn-Woan Lowe ◽  
...  
Keyword(s):  
Cell Differentiation ◽  
Epithelial Cell ◽  
Actin Cytoskeleton ◽  
Cross Talk ◽  
Lung Development ◽  
Trna Synthetase ◽  
Cell Junctions ◽  
Aminoacyl Trna Synthetase ◽  
Multifunctional Protein ◽  
Cell Cell

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.

cAMP-dependent protein kinase regulates renal epithelial cell properties

1991 ◽  
Vol 260 (6) ◽  
pp. C1290-C1299 ◽  
Author(s):  
K. Amsler ◽  
S. Ghatani ◽  
B. A. Hemmings
Keyword(s):  
Protein Kinase ◽  
Epithelial Cell ◽  
Cell Line ◽  
Cell Junctions ◽  
Kinetic Properties ◽  
Wild Type ◽  
Dependent Protein Kinase ◽  
Renal Epithelial Cell ◽  
Camp Dependent Protein Kinase ◽  
Dependent Protein

Previous studies have implicated adenosine 3',5'-cyclic monophosphate (cAMP)-dependent protein kinase (PKA) in regulation of both growth and expression of differentiated function in the pig renal epithelial cell, LLC-PK1. To investigate this possible regulatory mechanism, we compared growth behavior, morphology, and appearance of two differentiated functions, Na-hexose symport (SYMP) and gamma-glutamyl transpeptidase (gamma-GT), in the LLC-PK1 line and two PKA-deficient mutants (FIB4 and FIB6). Compared with the wild-type cell line, the mutant lines continued to proliferate at higher population densities and exhibited altered cell morphology, poorer formation of the brush-border structure, and decreased or lack of expression of SYMP and gamma-GT activities. Wild-type and mutant cells exhibit an identical logarithmic growth rate. Both lines form cell-cell junctions and exhibit identical kinetic properties of expressed SYMP activity. These results strongly support the hypothesis that PKA modulates a defined subset of cellular processes, including aspects of growth control and expression of the differentiated phenotype, in this renal epithelial cell line.

Effect of stretch on structural integrity and micromechanics of human alveolar epithelial cell monolayers exposed to thrombin

2006 ◽  
Vol 290 (6) ◽  
pp. L1104-L1110 ◽  
Author(s):  
Xavier Trepat ◽  
Ferranda Puig ◽  
Nuria Gavara ◽  
Jeffrey J. Fredberg ◽  
Ramon Farre ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Epithelial Cell ◽  
Structural Integrity ◽  
Alveolar Epithelial Cell ◽  
Compressive Strain ◽  
Cell Junctions ◽  
Cell Monolayers ◽  
Alveolar Epithelial ◽  
Epithelial Cell Monolayers ◽  
Human Alveolar Epithelial Cell

Alveolar epithelial cells in patients with acute lung injury subjected to mechanical ventilation are exposed to increased procoagulant activity and mechanical strain. Thrombin induces epithelial cell stiffening, contraction, and cytoskeletal remodeling, potentially compromising the balance of forces at the alveolar epithelium during cell stretching. This balance can be further compromised by the loss of integrity of cell-cell junctions in the injured epithelium. The aim of this work was to study the effect of stretch on the structural integrity and micromechanics of human alveolar epithelial cell monolayers exposed to thrombin. Confluent and subconfluent cells (A549) were cultured on collagen-coated elastic substrates. After exposure to thrombin (0.5 U/ml), a stepwise cell stretch (20%) was applied with a vacuum-driven system mounted on an inverted microscope. The structural integrity of the cell monolayers was assessed by comparing intercellular and intracellular strains within the monolayer. Strain was measured by tracking beads tightly bound to the cell surface. Simultaneously, cell viscoelasticity was measured using optical magnetic twisting cytometry. In confluent cells, thrombin did not induce significant changes in transmission of strain from the substrate to overlying cells. By contrast, thrombin dramatically impaired the ability of subconfluent cells to follow imposed substrate deformation. Upon substrate unstretching, thrombin-treated subconfluent cells exhibited compressive strain (9%). Stretch increased stiffness (56–62%) and decreased cell hysteresivity (13–22%) of vehicle cells. By contrast, stretch did not increase stiffness of thrombin-treated cells, suggesting disruption of cytoskeletal structures. Our findings suggest that thrombin could exacerbate epithelial barrier dysfunction in injured lungs subjected to mechanical ventilation.

scholarly journals Keratin intermediate filaments: intermediaries of epithelial cell migration

2019 ◽  
Vol 63 (5) ◽  
pp. 521-533 ◽  
Author(s):  
Sungjun Yoon ◽  
Rudolf E. Leube
Keyword(s):  
Cell Migration ◽  
Epithelial Cell ◽  
Epithelial Cells ◽  
Biomechanical Properties ◽  
Biochemical Properties ◽  
Cell Junctions ◽  
Epithelial Tissue ◽  
Post Translational Modification ◽  
Cell Sheets ◽  
Epithelial Cell Migration

Abstract Migration of epithelial cells is fundamental to multiple developmental processes, epithelial tissue morphogenesis and maintenance, wound healing and metastasis. While migrating epithelial cells utilize the basic acto-myosin based machinery as do other non-epithelial cells, they are distinguished by their copious keratin intermediate filament (KF) cytoskeleton, which comprises differentially expressed members of two large multigene families and presents highly complex patterns of post-translational modification. We will discuss how the unique mechanophysical and biochemical properties conferred by the different keratin isotypes and their modifications serve as finely tunable modulators of epithelial cell migration. We will furthermore argue that KFs together with their associated desmosomal cell–cell junctions and hemidesmosomal cell–extracellular matrix (ECM) adhesions serve as important counterbalances to the contractile acto-myosin apparatus either allowing and optimizing directed cell migration or preventing it. The differential keratin expression in leaders and followers of collectively migrating epithelial cell sheets provides a compelling example of isotype-specific keratin functions. Taken together, we conclude that the expression levels and specific combination of keratins impinge on cell migration by conferring biomechanical properties on any given epithelial cell affecting cytoplasmic viscoelasticity and adhesion to neighboring cells and the ECM.

scholarly journals Expansion microscopy of C. elegans

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Chih-Chieh (Jay) Yu ◽  
Nicholas C Barry ◽  
Asmamaw T Wassie ◽  
Anubhav Sinha ◽  
Abhishek Bhattacharya ◽  
...  
Keyword(s):  
Gene Expression ◽  
Expression Analysis ◽  
Gene Expression Analysis ◽  
Linear Expansion ◽  
Fluorescent Proteins ◽  
Synaptic Proteins ◽  
Cell Junctions ◽  
Anatomical Structures ◽  
C Elegans ◽  
Endogenous Proteins

We recently developed expansion microscopy (ExM), which achieves nanoscale-precise imaging of specimens at ~70 nm resolution (with ~4.5x linear expansion) by isotropic swelling of chemically processed, hydrogel-embedded tissue. ExM of C. elegans is challenged by its cuticle, which is stiff and impermeable to antibodies. Here we present a strategy, expansion of C. elegans (ExCel), to expand fixed, intact C. elegans. ExCel enables simultaneous readout of fluorescent proteins, RNA, DNA location, and anatomical structures at resolutions of ~65–75 nm (3.3–3.8x linear expansion). We also developed epitope-preserving ExCel, which enables imaging of endogenous proteins stained by antibodies, and iterative ExCel, which enables imaging of fluorescent proteins after 20x linear expansion. We demonstrate the utility of the ExCel toolbox for mapping synaptic proteins, for identifying previously unreported proteins at cell junctions, and for gene expression analysis in multiple individual neurons of the same animal.

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