Activity-induced fluidization of arrested coalescence in fusion of cellular aggregates

Ongenae, Steven; Cuvelier, Maxim; Vangheel, Jef; Ramón, Herman; Smeets, Bart

doi:10.1101/2021.02.26.433001

Cited by 2 publications

(1 citation statement)

References 25 publications

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“…Several studies have investigated the influence of different factors such as ROCK inhibitor and blebbistatin (Susienka et al, 2016), spheroid size (Olsen et al, 2015), cell type (and ratio) (Susienka et al, 2016;Kim et al, 2018;Song et al, 2019), and tissue maturation (Hajdu et al, 2010;Rago et al, 2009;Omelyanenko et al, 2020;Hall et al, 2021) on fusion behavior. Moreover, in silico models have been developed to gain further insight into the kinetics of spheroid fusion (Kosztin et al, 2012;Ongenae et al, 2021;McCune et al, 2014). These models can benefit from dedicated in vitro screening studies not only to improve them but also as a basis for model validation.…”

Section: Introductionmentioning

confidence: 99%

A platform for automated and label-free monitoring of morphological features and kinetics of spheroid fusion

Deckers

Hall

Papantoniou

et al. 2022

Front. Bioeng. Biotechnol.

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Spheroids are widely applied as building blocks for biofabrication of living tissues, where they exhibit spontaneous fusion toward an integrated structure upon contact. Tissue fusion is a fundamental biological process, but due to a lack of automated monitoring systems, the in-depth characterization of this process is still limited. Therefore, a quantitative high-throughput platform was developed to semi-automatically select doublet candidates and automatically monitor their fusion kinetics. Spheroids with varying degrees of chondrogenic maturation (days 1, 7, 14, and 21) were produced from two different cell pools, and their fusion kinetics were analyzed via the following steps: (1) by applying a novel spheroid seeding approach, the background noise was decreased due to the removal of cell debris while a sufficient number of doublets were still generated. (2) The doublet candidates were semi-automatically selected, thereby reducing the time and effort spent on manual selection. This was achieved by automatic detection of the microwells and building a random forest classifier, obtaining average accuracies, sensitivities, and precisions ranging from 95.0% to 97.4%, from 51.5% to 92.0%, and from 66.7% to 83.9%, respectively. (3) A software tool was developed to automatically extract morphological features such as the doublet area, roundness, contact length, and intersphere angle. For all data sets, the segmentation procedure obtained average sensitivities and precisions ranging from 96.8% to 98.1% and from 97.7% to 98.8%, respectively. Moreover, the average relative errors for the doublet area and contact length ranged from 1.23% to 2.26% and from 2.30% to 4.66%, respectively, while the average absolute errors for the doublet roundness and intersphere angle ranged from 0.0083 to 0.0135 and from 10.70 to 13.44°, respectively. (4) The data of both cell pools were analyzed, and an exponential model was used to extract kinetic parameters from the time-series data of the doublet roundness. For both cell pools, the technology was able to characterize the fusion rate and quality in an automated manner and allowed us to demonstrate that an increased chondrogenic maturity was linked with a decreased fusion rate. The platform is also applicable to other spheroid types, enabling an increased understanding of tissue fusion. Finally, our approach to study spheroid fusion over time will aid in the design of controlled fabrication of “assembloids” and bottom-up biofabrication of living tissues using spheroids.

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Section: Introductionmentioning

confidence: 99%

A platform for automated and label-free monitoring of morphological features and kinetics of spheroid fusion

Deckers

Hall

Papantoniou

et al. 2022

Front. Bioeng. Biotechnol.

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Sculpting tissues by phase transitions

Lenne

Trivedi

2022

Nat Commun

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Biological systems display a rich phenomenology of states that resemble the physical states of matter - solid, liquid and gas. These phases result from the interactions between the microscopic constituent components - the cells - that manifest in macroscopic properties such as fluidity, rigidity and resistance to changes in shape and volume. Looked at from such a perspective, phase transitions from a rigid to a flowing state or vice versa define much of what happens in many biological processes especially during early development and diseases such as cancer. Additionally, collectively moving confluent cells can also lead to kinematic phase transitions in biological systems similar to multi-particle systems where the particles can interact and show sub-populations characterised by specific velocities. In this Perspective we discuss the similarities and limitations of the analogy between biological and inert physical systems both from theoretical perspective as well as experimental evidence in biological systems. In understanding such transitions, it is crucial to acknowledge that the macroscopic properties of biological materials and their modifications result from the complex interplay between the microscopic properties of cells including growth or death, neighbour interactions and secretion of matrix, phenomena unique to biological systems. Detecting phase transitions in vivo is technically difficult. We present emerging approaches that address this challenge and may guide our understanding of the organization and macroscopic behaviour of biological tissues.

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Activity-induced fluidization of arrested coalescence in fusion of cellular aggregates

Cited by 2 publications

References 25 publications

A platform for automated and label-free monitoring of morphological features and kinetics of spheroid fusion

A platform for automated and label-free monitoring of morphological features and kinetics of spheroid fusion

Sculpting tissues by phase transitions

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