Functional differentiation of alveolar type II epithelial cells in vitro: Effects of cell shape, cell-matrix interactions and cell-cell interactions

Author(s):  
John M. Shannon ◽  
Robert J. Mason ◽  
Susan D. Jennings
2010 ◽  
Vol 26 (6) ◽  
pp. 367-374 ◽  
Author(s):  
Tiffany M Robb ◽  
Michael J Rogers ◽  
Suann S Woodward ◽  
Simon S Wong ◽  
Mark L Witten

2004 ◽  
Vol 287 (1) ◽  
pp. L104-L110 ◽  
Author(s):  
Xiaohui Fang ◽  
Yuanlin Song ◽  
Rachel Zemans ◽  
Jan Hirsch ◽  
Michael A. Matthay

Previous studies have used fluid-instilled lungs to measure net alveolar fluid transport in intact animal and human lungs. However, intact lung studies have two limitations: the contribution of different distal lung epithelial cells cannot be studied separately, and the surface area for fluid absorption can only be approximated. Therefore, we developed a method to measure net vectorial fluid transport in cultured rat alveolar type II cells using an air-liquid interface. The cells were seeded on 0.4-μm microporous inserts in a Transwell system. At 96 h, the transmembrane electrical resistance reached a peak level (1,530 ± 115 Ω·cm2) with morphological evidence of tight junctions. We measured net fluid transport by placing 150 μl of culture medium containing 0.5 μCi of 131I-albumin on the apical side of the polarized cells. Protein permeability across the cell monolayer, as measured by labeled albumin, was 1.17 ± 0.34% over 24 h. The change in concentration of 131I-albumin in the apical fluid was used to determine the net fluid transported across the monolayer over 12 and 24 h. The net basal fluid transport was 0.84 μl·cm−2·h−1. cAMP stimulation with forskolin and IBMX increased fluid transport by 96%. Amiloride inhibited both the basal and stimulated fluid transport. Ouabain inhibited basal fluid transport by 93%. The cultured cells retained alveolar type II-like features based on morphologic studies, including ultrastructural imaging. In conclusion, this novel in vitro system can be used to measure net vectorial fluid transport across cultured, polarized alveolar epithelial cells.


2019 ◽  
Vol 25 (3) ◽  
pp. 753-761 ◽  
Author(s):  
Warren Colomb ◽  
Matthew Osmond ◽  
Charles Durfee ◽  
Melissa D. Krebs ◽  
Susanta K. Sarkar

AbstractThe absence of quantitative in vitro cell–extracellular matrix models represents an important bottleneck for basic research and human health. Randomness of cellular distributions provides an opportunity for the development of a quantitative in vitro model. However, quantification of the randomness of random cell distributions is still lacking. In this paper, we have imaged cellular distributions in an alginate matrix using a multiview light sheet microscope and developed quantification metrics of randomness by modeling it as a Poisson process, a process that has constant probability of occurring in space or time. We imaged fluorescently labeled human mesenchymal stem cells embedded in an alginate matrix of thickness greater than 5 mm with $\sim\! {\rm 2}{\rm. 9} \pm {\rm 0}{\rm. 4}\,\mu {\rm m}$ axial resolution, the mean full width at half maximum of the axial intensity profiles of fluorescent particles. Simulated randomness agrees well with the experiments. Quantification of distributions and validation by simulations will enable quantitative study of cell–matrix interactions in tissue models.


2020 ◽  
Vol 85-86 ◽  
pp. 15-33 ◽  
Author(s):  
J.C. Ashworth ◽  
J.L. Thompson ◽  
J.R. James ◽  
C.E. Slater ◽  
S. Pijuan-Galitó ◽  
...  

F1000Research ◽  
2019 ◽  
Vol 8 ◽  
pp. 357
Author(s):  
Diane Lee ◽  
Mark Chambers

The epithelial lining of the lung is often the first point of interaction between the host and inhaled pathogens, allergens and medications. Epithelial cells are therefore the main focus of studies which aim to shed light on host-pathogen interactions, to dissect the mechanisms of local host immunity and study toxicology. If these studies are not to be conducted exclusively in vivo, it is imperative that in vitro models are developed with a high in vitro-in vivo correlation. We describe here a co-culture bilayer model of the bovine alveolus, designed to overcome some of the limitations encountered with mono-culture and live animal models. Our system includes bovine pulmonary arterial endothelial cells (BPAECs) seeded onto a permeable membrane in 24 well Transwell format. The BPAECs are overlaid with immortalised bovine alveolar type II epithelial cells and the bilayer cultured at air-liquid interface for 14 days before use; in our case to study host-mycobacterial interactions. Characterisation of novel cell lines and the bilayer model have provided compelling evidence that immortalised bovine alveolar type II cells are an authentic substitute for primary alveolar type II cells and their culture as a bilayer in conjunction with BPAECs provides a physiologically relevant in vitro model of the bovine alveolus.   The bilayer model may be used to study dynamic intracellular and extracellular host-pathogen interactions, using proteomics, genomics, live cell imaging, in-cell ELISA and confocal microscopy. The model presented in this article enables other researchers to establish an in vitro model of the bovine alveolus that is easy to set up, malleable and serves as a comparable alternative to in vivo models, whilst allowing study of early host-pathogen interactions, currently not feasible in vivo. The model therefore achieves one of the 3Rs objectives in that it replaces the use of animals in research of bovine respiratory diseases.


2020 ◽  
Author(s):  
Austin G. Gouldin ◽  
Jennifer L. Puetzer

AbstractIn connective tissues there is a clear link between increasing age and degeneration. It is believed advanced glycation end-products (AGEs) play a central role in this degeneration. AGEs are sugar induced non-enzymatic crosslinks which accumulate in collagen with age and diabetes, altering tissue mechanics and cellular function. Despite ample correlative evidence linking collagen glycation to degeneration, little is known how AGEs impact cell-matrix interactions, limiting therapeutic options. One reason for this limited understanding is AGEs are typically induced in vitro using high concentrations of ribose which decrease cell viability and make it impossible to investigate cell-matrix interactions. The objective of this study was to develop a system to trigger AGE accumulation while maintaining cell viability. Using cell-seeded high density collagen gels, we investigated the effect of two different systems for AGE induction, ribose at low concentrations (30, 100, and 200 mM) over 15 days of culture and riboflavin (0.25 mM and 0.75mM) induced with blue light for 40 seconds. We found ribose and riboflavin with blue light are capable of producing a wide range of AGE crosslinks which match and/or exceed reported human AGE levels for various tissues, ages, and diseases, without affecting cell viability and metabolism. Interestingly, a single 40 second treatment of riboflavin and blue light produced similar levels of AGEs as 3 days of 100 mM ribose treatment and matched aged mouse tendon AGE levels. This riboflavin treatment option is an exciting means to trigger AGE crosslinks on demand in vivo or in vitro without impacting cell metabolism or viability and holds great promise for further unraveling the mechanism of AGEs in age and diabetes related tissue degeneration.


1999 ◽  
Vol 276 (3) ◽  
pp. L481-L490 ◽  
Author(s):  
Rama K. Mallampalli ◽  
Erik J. Peterson ◽  
Aaron Brent Carter ◽  
Ronald G. Salome ◽  
Satya N. Mathur ◽  
...  

Ceramide is a bioactive lipid mediator that has been observed to induce apoptosis in vitro. The purpose of this study was to determine whether endogenous ceramide, generated in response to in vivo administration of tumor necrosis factor-α (TNF-α), increases apoptosis in primary rat alveolar type II epithelial cells. Intratracheal instillation of TNF-α (5 μg) produced a decrease in sphingomyelin and activation of a neutral sphingomyelinase. These changes were associated with a significant increase in lung ceramide content. TNF-α concomitantly activated the p42/44 extracellular signal-related kinases and induced nuclear factor-κB activation in the lung. Hypodiploid nuclei studies revealed that intratracheal TNF-α did not increase type II cell apoptosis compared with that in control cells after isolation. A novel observation from separate in vitro studies demonstrated that type II cells undergo a gradual increase in apoptosis after time in culture, a process that was accelerated by exposure of cells to ultraviolet light. However, culture of cells with a cell-permeable ceramide, TNF-α, or a related ligand, anti-CD95, did not increase apoptosis above the control level. The results suggest that ceramide resulting from TNF-α activation of sphingomyelin hydrolysis might activate the mitogen-activated protein kinase and nuclear factor-κB pathways without increasing programmed cell death in type II cells.


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