Stiffness as an Effector of Lung Branching Morphogenesis

2012 ◽  
Author(s):  
Kelly C. Clause ◽  
Tatiana Segura ◽  
Thomas H. Barker
Keyword(s):  
Cell Fate ◽  
In Vitro Study ◽  
Branching Morphogenesis ◽  
Substrate Stiffness ◽  
Tissue Morphogenesis ◽  
Mechanical Stiffness ◽  
Physical Cues ◽  
Direct Cell ◽  
Cleft Formation

Growing evidence suggests that physical microenvironments and mechanical stresses direct cell fate in developing tissues. However, how these physical properties affect morphogenesis remains unknown. We show here that ECM mechanical properties, i.e. stiffness, reproduced by using hydrogel, guide tissue morphogenesis in the developing lung bud. In particular, decreasing substrate stiffness in cultured lung buds resulted in an inhibition of appropriate cleft formation and a resulting enlargement of epithelial buds. These findings suggest that the magnitude of mechanical stiffness across the lung bud alters the branching pattern. Additionally, physically designed hydrogel material is a valuable tool for producing the specific microenvironment to explore how physical cues affect and alter tissue morphogenesis for in vitro study.

scholarly journals A Graded Multifunctional Hybrid Scaffold with Superparamagnetic Ability for Periodontal Regeneration

2018 ◽  
Vol 19 (11) ◽  
pp. 3604 ◽  
Author(s):  
Simone Sprio ◽  
Elisabetta Campodoni ◽  
Monica Sandri ◽  
Lorenzo Preti ◽  
Tobias Keppler ◽  
...  
Keyword(s):  
Cell Fate ◽  
Alveolar Bone ◽  
Tape Casting ◽  
Periodontal Regeneration ◽  
Dental Tissue ◽  
Hybrid Scaffold ◽  
Dental Tissues ◽  
Biomineralization Process ◽  
Direct Cell

The regeneration of dental tissues is a still an unmet clinical need; in fact, no therapies have been completely successful in regenerating dental tissue complexes such as periodontium, which is also due to the lack of scaffolds that are able to guide and direct cell fate towards the reconstruction of different mineralized and non-mineralized dental tissues. In this respect, the present work develops a novel multifunctional hybrid scaffold recapitulating the different features of alveolar bone, periodontal ligament, and cementum by integrating the biomineralization process, and tape casting and electrospinning techniques. The scaffold is endowed with a superparamagnetic ability, thanks to the use of a biocompatible, bioactive superparamagnetic apatite phase, as a mineral component that is able to promote osteogenesis and to be activated by remote magnetic signals. The periodontal scaffold was obtained by engineering three different layers, recapitulating the relevant compositional and microstructural features of the target tissues, into a monolithic multifunctional graded device. Physico-chemical, morphological, and ultrastructural analyses, in association with preliminary in vitro investigations carried out with mesenchymal stem cells, confirm that the final scaffold exhibits a good mimicry of the periodontal tissue complex, with excellent cytocompatibility and cell viability, making it very promising for regenerative applications in dentistry.

scholarly journals Consistent apparent Young’s modulus of human embryonic stem cells and derived cell types stabilized by substrate stiffness regulation promotes lineage specificity maintenance

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Anqi Guo ◽  
Bingjie Wang ◽  
Cheng Lyu ◽  
Wenjing Li ◽  
Yaozu Wu ◽  
...  
Keyword(s):  
Stem Cell ◽  
Cell Fate ◽  
Cell Expansion ◽  
Embryonic Stem ◽  
Cell Types ◽  
Substrate Stiffness ◽  
Cell Stage ◽  
Cytoskeletal Organization ◽  
Lineage Specificity

Abstract Background Apparent Young’s modulus (AYM), which reflects the fundamental mechanical property of live cells measured by atomic force microscopy and is determined by substrate stiffness regulated cytoskeletal organization, has been investigated as potential indicators of cell fate in specific cell types. However, applying biophysical cues, such as modulating the substrate stiffness, to regulate AYM and thereby reflect and/or control stem cell lineage specificity for downstream applications, remains a primary challenge during in vitro stem cell expansion. Moreover, substrate stiffness could modulate cell heterogeneity in the single-cell stage and contribute to cell fate regulation, yet the indicative link between AYM and cell fate determination during in vitro dynamic cell expansion (from single-cell stage to multi-cell stage) has not been established. Results Here, we show that the AYM of cells changed dynamically during passaging and proliferation on substrates with different stiffness. Moreover, the same change in substrate stiffness caused different patterns of AYM change in epithelial and mesenchymal cell types. Embryonic stem cells and their derived progenitor cells exhibited distinguishing AYM changes in response to different substrate stiffness that had significant effects on their maintenance of pluripotency and/or lineage-specific characteristics. On substrates that were too rigid or too soft, fluctuations in AYM occurred during cell passaging and proliferation that led to a loss in lineage specificity. On a substrate with ‘optimal’ stiffness (i.e., 3.5 kPa), the AYM was maintained at a constant level that was consistent with the parental cells during passaging and proliferation and led to preservation of lineage specificity. The effects of substrate stiffness on AYM and downstream cell fate were correlated with intracellular cytoskeletal organization and nuclear/cytoplasmic localization of YAP. Conclusions In summary, this study suggests that optimal substrate stiffness regulated consistent AYM during passaging and proliferation reflects and contributes to hESCs and their derived progenitor cells lineage specificity maintenance, through the underlying mechanistic pathways of stiffness-induced cytoskeletal organization and the downstream YAP signaling. These findings highlighted the potential of AYM as an indicator to select suitable substrate stiffness for stem cell specificity maintenance during in vitro expansion for regenerative applications.

The role of interstitial collagens in cleft formation of mouse embryonic submandibular gland during initial branching

Development ◽  
1988 ◽  
Vol 103 (2) ◽  
pp. 259-267 ◽  
Author(s):  
Y. Fukuda ◽  
Y. Masuda ◽  
J. Kishi ◽  
Y. Hashimoto ◽  
T. Hayakawa ◽  
...  
Keyword(s):  
Dental Pulp ◽  
Electron Microscopic Observation ◽  
Branching Morphogenesis ◽  
Collagen Fibrils ◽  
Electron Microscopic ◽  
Active Involvement ◽  
Interstitial Collagens ◽  
Cleft Formation

An interstitial collagenase was purified from the explant medium of bovine dental pulp and was shown to degrade collagens I and III but not IV and V. The enzyme halted cleft initiation in the epithelium of 12-day mouse embryonic submandibular glands in vitro, indicating the active involvement of interstitial collagens in the branching morphogenesis. Transmission electron microscopic observation of the intact 12-day gland without any clefts showed the scattered localization of a few collagen fibrils at the epithelial-mesenchymal interface of the bulb and also revealed the presence of numerous microfibrils around the stalk. Collagen bundles were regularly seen close to the wavy basal lamina at the bottom of clefts of the intact 13-day gland and 12-day gland cultured for 17 h under normal conditions. Mesenchymal cells were found in the clefts together with the frequent localization of peripheral nerve fibres and capillary endothelial cells. The collagen bundles were more often observed in the 12-day gland cultured in the presence of bovine dental pulp collagenase inhibitor, which had been shown to enhance cleft formation. In contrast, collagen fibrils were rarely found at the epithelial-mesenchymal interface of the 12-day gland cultured in the presence of Clostridial or bovine dental pulp collagenase. The findings indicated that the formation of interstitial collagen bundles is essential to form clefts in the epithelium both in vivo and in vitro.

scholarly journals Controlling Self-Renewal and Differentiation of Stem Cells via Mechanical Cues

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Michele M. Nava ◽  
Manuela T. Raimondi ◽  
Riccardo Pietrabissa
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell Fate ◽  
Cell Response ◽  
Recent Literature ◽  
Focal Adhesions ◽  
Substrate Stiffness ◽  
Self Renewal ◽  
Mechanical Factors

The control of stem cell responsein vitro, including self-renewal and lineage commitment, has been proved to be directed by mechanical cues, even in the absence of biochemical stimuli. Through integrin-mediated focal adhesions, cells are able to anchor onto the underlying substrate, sense the surrounding microenvironment, and react to its properties. Substrate-cell and cell-cell interactions activate specific mechanotransduction pathways that regulate stem cell fate. Mechanical factors, including substrate stiffness, surface nanotopography, microgeometry, and extracellular forces can all have significant influence on regulating stem cell activities. In this paper, we review all the most recent literature on the effect of purely mechanical cues on stem cell response, and we introduce the concept of “force isotropy” relevant to cytoskeletal forces and relevant to extracellular loads acting on cells, to provide an interpretation of how the effects of insoluble biophysical signals can be used to direct stem cells fatein vitro.

scholarly journals Ngn1 inhibits astrogliogenesis through induction of miR-9 during neuronal fate specification

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Jing Zhao ◽  
Quan Lin ◽  
Kevin J Kim ◽  
Faranak D Dardashti ◽  
Jennifer Kim ◽  
...  
Keyword(s):  
Cell Fate ◽  
Epigenetic Regulation ◽  
In Vitro Study ◽  
Fate Specification ◽  
Neuronal Fate ◽  
Non Coding Rna ◽  
Neuronal Fate Specification ◽  
Stat Pathway

It has been postulated that a proneural factor, neurogenin 1 (Ngn1), simultaneously activates the neurogenic program and inhibits the alternative astrogliogenic program when specifying the neuronal fate. While Ngn1 substantially suppresses the activation of the astrogliogenic Jak-Stat pathway, the underlying molecular mechanism was unknown. Here, by employing in vivo and in vitro approaches, we report that Ngn1 binds to the promoter of a brain-enriched microRNA, miR-9, and activates its expression during neurogenesis. Subsequently, our in vitro study showed that miR-9 directly targets mRNAs of Lifr-beta, Il6st (gp130), and Jak1 to down-regulate these critical upstream components of the Jak-Stat pathway, achieving inhibition of Stat phosphorylation and consequently, suppression of astrogliogenesis. This study revealed Ngn1 modulated non-coding RNA epigenetic regulation during cell fate specifications.

scholarly journals From Clones to Buds and Branches: The Use of Lung Organoids to Model Branching Morphogenesis Ex Vivo

2021 ◽  
Vol 9 ◽  
Author(s):  
Ana Ivonne Vazquez-Armendariz ◽  
Susanne Herold
Keyword(s):  
Cell Fate ◽  
Molecular Mechanisms ◽  
Ex Vivo ◽  
3D Culture ◽  
Cell Types ◽  
Branching Morphogenesis ◽  
Cell Fate Decisions ◽  
Culture Systems

Three-dimensional (3D) organoid culture systems have rapidly emerged as powerful tools to study organ development and disease. The lung is a complex and highly specialized organ that comprises more than 40 cell types that offer several region-specific roles. During organogenesis, the lung goes through sequential and morphologically distinctive stages to assume its mature form, both structurally and functionally. As branching takes place, multipotent epithelial progenitors at the distal tips of the growing/bifurcating epithelial tubes progressively become lineage-restricted, giving rise to more differentiated and specialized cell types. Although many cellular and molecular mechanisms leading to branching morphogenesis have been explored, deeper understanding of biological processes governing cell-fate decisions and lung patterning is still needed. Given that these distinct processes cannot be easily analyzedin vivo, 3D culture systems have become a valuable platform to study organogenesisin vitro. This minireview focuses on the current lung organoid systems that recapitulate developmental events occurring before and during branching morphogenesis. In addition, we also discuss their limitations and future directions.

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