Substrate stiffness- and topography-dependent differentiation of annulus fibrosus-derived stem cells is regulated by Yes-associated protein

In many cell types, several cellular processes, such as differentiation of stem/precursor cells, maintenance of differentiated phenotype, motility, adhesion, growth, and survival, strictly depend on the stiffness of extracellular matrix that,in vivo, characterizes their correspondent organ and tissue. In the liver, the stromal rigidity is essential to obtain the correct organ physiology whereas any alteration causes liver cell dysfunctions. The rigidity of the substrate is an element no longer negligible for the cultivation of several cell types, so that many data so far obtained, where cells have been cultured on plastic, could be revised. Regarding liver cells, standard culture conditions lead to the dedifferentiation of primary hepatocytes, transdifferentiation of stellate cells into myofibroblasts, and loss of fenestration of sinusoidal endothelium. Furthermore, standard cultivation of liver stem/precursor cells impedes an efficient execution of the epithelial/hepatocyte differentiation program, leading to the expansion of a cell population expressing only partially liver functions and products. Overcoming these limitations is mandatory for any approach of liver tissue engineering. Here we propose cell lines asin vitromodels of liver stem cells and hepatocytes and an innovative culture method that takes into account the substrate stiffness to obtain, respectively, a rapid and efficient differentiation process and the maintenance of the fully differentiated phenotype.

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Murine Osteochondral Stem Cells Express Collagen Type I More Strongly on PDMS Substrates Than on Tissue Culture Plastic

Volume 1A: Abdominal Aortic Aneurysms; Active and Reactive Soft Matter; Atherosclerosis; BioFluid Mechanics; Education; Biotransport Phenomena; Bone, Joint and Spine Mechanics; Brain Injury; Cardiac Mechanics; Cardiovascular Devices, Fluids and Imaging; Cartilage and Disc Mechanics; Cell and Tissue Engineering; Cerebral Aneurysms; Computational Biofluid Dynamics; Device Design, Human Dynamics, and Rehabilitation; Drug Delivery and Disease Treatment; Engineered Cellular Environments ◽

10.1115/sbc2013-14272 ◽

2013 ◽

Author(s):

William S. Van Dyke ◽

Ozan Akkus ◽

Eric Nauman

Keyword(s):

Stem Cells ◽

Mesenchymal Stem Cells ◽

Bone Cells ◽

Stem Cell Differentiation ◽

Collagen Type I ◽

Fiber Formation ◽

Substrate Stiffness ◽

Type I ◽

Differentiation Potential

The discovery of the multipotent lineage of mesenchymal stem cells has dawned a new age in tissue engineering, where an autologous cell-seeded scaffold can be implanted into different therapeutic sites. Mesenchymal stem cells have been reported to differentiate into numerous anchorage-dependent cell phenotypes, including neurons, adipocytes, myoblasts, chondrocytes, tenocytes, and osteoblasts. A seminal work detailing that mesenchymal stem cells can be directed towards differentiation of different cell types by substrate stiffness alone [1] has led to numerous studies attempting to understand how cells can sense the stiffness of their substrate [2–3] Substrate stiffness has been shown to be an inducer of stem cell differentiation. MSCs on extremely soft substrates (250 Pa), similar to the stiffness of bone marrow, became quiescent but still retained their multipotency [4]. Elastic substrates in the stiffness range of 34 kPa revealed MSCs with osteoblast morphology, and osteocalcin along with other osteoblast markers were expressed [1]. However, osteogenesis has been found to increase on much stiffer (20–80 kPa) [5–6] (400 kPa) [7] as well as much softer substrates (75 Pa) [8]. Overall, cells have increased projected cell area and proliferation on stiffer substrates, leading to higher stress fiber formation. This study seeks to understand if the stiffness of the substrate has any effect on the differentiation potential of osteochondral progenitor cells into bone cells, using an in vitro dual fluorescent mouse model.

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A newly identified mechanism involved in regulation of human mesenchymal stem cells by fibrous substrate stiffness

Acta Biomaterialia ◽

10.1016/j.actbio.2016.06.034 ◽

2016 ◽

Vol 42 ◽

pp. 247-257 ◽

Cited By ~ 33

Author(s):

Huihua Yuan ◽

Yaxian Zhou ◽

Ming-Song Lee ◽

Yanzhong Zhang ◽

Wan-Ju Li

Keyword(s):

Stem Cells ◽

Mesenchymal Stem Cells ◽

Human Mesenchymal Stem Cells ◽

Substrate Stiffness

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Characterizing the effect of substrate stiffness on neural stem cell differentiation

MRS Proceedings ◽

10.1557/opl.2012.1559 ◽

2012 ◽

Vol 1498 ◽

pp. 47-52

Author(s):

Colleen T. Curley ◽

Kristen Fanale ◽

Sabrina S. Jedlicka

Keyword(s):

Stem Cells ◽

Cell Differentiation ◽

Neural Stem Cells ◽

Cortical Neurons ◽

Type I Collagen ◽

Stem Cell Differentiation ◽

Synaptic Proteins ◽

Substrate Stiffness ◽

Type I ◽

Polyacrylamide Gels

ABSTRACTDifferentiated neurons (dorsal root ganglia and cortical neurons) have been shown to develop longer neurite extensions on softer materials than stiffer ones, but previous studies do not address the ability of neural stem cells to undergo differentiation as a result of material elasticity. In this study, we investigate neuronal differentiation of C17.2 neural stem cells due to growth on polyacrylamide gels of variable elastic moduli. Neurite growth, synapse formation, and mode of division (asymmetric vs. symmetric) were all assessed to characterize differentiation. C17.2 neural stem cells were seeded onto polyacrylamide gels coated with Type I collagen. The cells were then serum starved over a 14 day period, fixed, and analyzed for biochemical markers of differentiation. For division studies, time-lapse imaging of cells on various substrates was performed during serum withdrawal using the Nikon Biostation. Division events were analyzed using ImageJ to quantify sizes of resulting daughter. Data shows that C17.2 cell differentiation (as dictated by number and type of division events) is dependent upon substrate stiffness, with softer polyacrylamide surfaces (140 Pa) leading to increased populations of neurons and increased neurite length. Our data also indicates that the ability of neural stem cells to express synaptic proteins and develop synapses is dependent upon material elasticity.

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