scholarly journals Imaging and Analysis of Cellular Locations in Three-Dimensional Tissue Models

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.

2017 ◽  
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. Our light-sheet microscope can image more than 5 mm thick optically clear samples with 2.9 ±0.4 μm depth-resolution. We applied our method to image fluorescently labeled human mesenchymal stem cells (hMSCs) embedded in an alginate matrix. 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.


2017 ◽  
Vol 14 (127) ◽  
pp. 20160877 ◽  
Author(s):  
X. Cui ◽  
Y. Hartanto ◽  
H. Zhang

Three-dimensional multicellular spheroids (MCSs) have a complex architectural structure, dynamic cell–cell/cell–matrix interactions and bio-mimicking in vivo microenvironment. As a fundamental building block for tissue reconstruction, MCSs have emerged as a powerful tool to narrow down the gap between the in vitro and in vivo model. In this review paper, we discussed the structure and biology of MCSs and detailed fabricating methods. Among these methods, the approach in microfluidics with hydrogel support for MCS formation is promising because it allows essential cell–cell/cell–matrix interactions in a confined space.


Author(s):  
Jonas F. Eichinger ◽  
Maximilian J. Grill ◽  
Iman Davoodi Kermani ◽  
Roland C. Aydin ◽  
Wolfgang A. Wall ◽  
...  

AbstractLiving soft tissues appear to promote the development and maintenance of a preferred mechanical state within a defined tolerance around a so-called set point. This phenomenon is often referred to as mechanical homeostasis. In contradiction to the prominent role of mechanical homeostasis in various (patho)physiological processes, its underlying micromechanical mechanisms acting on the level of individual cells and fibers remain poorly understood, especially how these mechanisms on the microscale lead to what we macroscopically call mechanical homeostasis. Here, we present a novel computational framework based on the finite element method that is constructed bottom up, that is, it models key mechanobiological mechanisms such as actin cytoskeleton contraction and molecular clutch behavior of individual cells interacting with a reconstructed three-dimensional extracellular fiber matrix. The framework reproduces many experimental observations regarding mechanical homeostasis on short time scales (hours), in which the deposition and degradation of extracellular matrix can largely be neglected. This model can serve as a systematic tool for future in silico studies of the origin of the numerous still unexplained experimental observations about mechanical homeostasis.


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

PLoS ONE ◽  
2011 ◽  
Vol 6 (3) ◽  
pp. e17833 ◽  
Author(s):  
Christian Franck ◽  
Stacey A. Maskarinec ◽  
David A. Tirrell ◽  
Guruswami Ravichandran

2021 ◽  
Author(s):  
Lewis S. Gaffney ◽  
Matthew B. Fisher ◽  
Donald O. Freytes

AbstractMuscle and tendon injuries are prevalent and range from minor sprains and strains to traumatic, debilitating injuries. However, the interactions between these tissues during injury and recovery remain unclear. Three-dimensional tissue models that incorporate both tissues and a physiologically relevant junction between muscle and tendon may aide in understanding how the two tissues interact. Here, we use tissue specific extracellular matrix (ECM) derived from muscle and tendon to determine how cells of each tissue interact with the microenvironment of the opposite tissue resulting in junction specific features. ECM materials were derived from the achilles tendon and gastrocnemius muscle, decellularized, and processed to form tissue specific pre-hydrogel digests. C2C12 myoblasts and tendon fibroblasts were cultured in tissue-specific ECM conditioned media or encapsulated in tissue-specific ECM hydrogels to determine cell-matrix interactions and the effects on a muscle-tendon junction marker, paxillin. ECM conditioned media had only a minor effect on upregulation of paxillin in cells cultured in monolayer. However, cells cultured within ECM hydrogels had 50-70% higher paxillin expression than cells cultured in type I collagen hydrogels. Contraction of the ECM hydrogels varied by the type of ECM used. Subsequent experiments with varying density of type I collagen (and thus contraction) showed no correlation between paxillin expression and the amount of gel contraction, suggesting that a constituent of the ECM was the driver of paxillin expression in the ECM hydrogels. Using tissue specific ECM allowed for the de-construction of the cell-matrix interactions similar to muscle-tendon junctions to study the expression of MTJ specific proteins.Impact StatementThe muscle-tendon junction is an important feature of muscle-tendon units; however, despite cross-talk between the two tissue types, it is overlooked in current research. Deconstructing the cell-matrix interactions will allow the opportunity to study significant junction specific features and markers that should be included in tissue models of the muscle-tendon unit, while gaining a deeper understanding of the natural junction. This research aims to inform future methods to engineer a more relevant multi-tissue platform to study the muscle-tendon unit.


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.


2005 ◽  
Vol 16 (11) ◽  
pp. 5070-5076 ◽  
Author(s):  
Hongmei Jiang ◽  
Frederick Grinnell

Fibroblast-3D collagen matrix culture provides a physiologically relevant model to study cell–matrix interactions. In tissues, fibroblasts are phagocytic cells, and in culture, they have been shown to ingest both fibronectin and collagen-coated latex particles. Compared with cells on collagen-coated coverslips, phagocytosis of fibronectin-coated beads by fibroblasts in collagen matrices was found to be reduced. This decrease could not be explained by integrin reorganization, tight binding of fibronectin beads to the collagen matrix, or differences in overall bead binding to the cells. Rather, entanglement of cellular dendritic extensions with collagen fibrils seemed to interfere with the ability of the extensions to interact with the beads. Moreover, once these extensions became entangled in the matrix, cells developed an integrin-independent component of adhesion. We suggest that cell–matrix entanglement represents a novel mechanism of cell anchorage that uniquely depends on the three-dimensional character of the matrix.


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