Insights into interstitial flow, shear stress, and mass transport effects on ECM heterogeneity in bioreactor-cultivated engineered cartilage hydrogels

Osteosarcoma (OS) is an aggressive bone cancer originating in the mesenchymal lineage. Prognosis for metastatic disease is poor, with a mortality rate of approximately 40%; OS is an aggressive disease for which new treatments are needed. All bone cells are sensitive to their mechanical/physical surroundings and changes in these surroundings can affect their behavior. However, it is not well understood how OS cells specifically respond to fluid movement, or substrate stiffness—two stimuli of relevance in the tumor microenvironment. We used cells from spontaneous OS tumors in a mouse engineered to have a bone-specific knockout of pRb-1 and p53 in the osteoblast lineage. We silenced Sox2 (which regulates YAP) and tested the effect of fluid flow shear stress (FFSS) and substrate stiffness on YAP expression/activity—which was significantly reduced by loss of Sox2, but that effect was reversed by FFSS but not by substrate stiffness. Osteogenic gene expression was also reduced in the absence of Sox2 but again this was reversed by FFSS and remained largely unaffected by substrate stiffness. Thus we described the effect of two distinct stimuli on the mechanosensory and osteogenic profiles of OS cells. Taken together, these data suggest that modulation of fluid movement through, or stiffness levels within, OS tumors could represent a novel consideration in the development of new treatments to prevent their progression.

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(Keynote) Electrolyte and Mass Transport Effects in CO2 Electroreduction

ECS Meeting Abstracts ◽

10.1149/ma2021-01471891mtgabs ◽

2021 ◽

Vol MA2021-01 (47) ◽

pp. 1891-1891

Author(s):

Marc Koper

Keyword(s):

Mass Transport ◽

Co2 Electroreduction ◽

Transport Effects ◽

Mass Transport Effects

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Separation of kinetic and mass transport effects in the electrolysis of formic acid in a flow-through cell

Electrochimica Acta ◽

10.1016/j.electacta.2018.10.088 ◽

2019 ◽

Vol 294 ◽

pp. 110-116 ◽

Cited By ~ 2

Author(s):

Qingxin Zhang ◽

Azam Sayadi ◽

Peter G. Pickup

Keyword(s):

Mass Transport ◽

Formic Acid ◽

Transport Effects ◽

Flow Through ◽

Mass Transport Effects

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Temporal gradient in shear-induced signaling pathway: involvement of MAP kinase, c-fos, and connexin43

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.2000.278.5.h1598 ◽

2000 ◽

Vol 278 (5) ◽

pp. H1598-H1605 ◽

Cited By ~ 68

Author(s):

Xuping Bao ◽

Craig B. Clark ◽

John A. Frangos

Keyword(s):

Shear Stress ◽

Mrna Expression ◽

Signaling Pathway ◽

Steady Shear ◽

Flow Shear ◽

Temporal Gradient ◽

Step Flow ◽

Shear Component ◽

Flow Shear Stress ◽

Impulse Flow

The effect of a temporal gradient in shear and steady shear on the activity of extracellular signal-regulated protein kinases 1 and 2 (ERK1/ERK2), c- fos, and connexin43 (Cx43) in human endothelial cells was investigated. Three laminar flow profiles (16 dyn/cm2), including impulse flow (shear stress abruptly applied for 3 s), ramp flow (shear stress smoothly transitioned at flow onset), and step flow (shear stress abruptly applied at flow onset) were utilized. Relative to static controls, impulse flow stimulated the phosphorylation of ERK1/ERK2 8.5- to 7.5-fold, respectively at 10 min, as well as the mRNA expression of c- fos 51-fold at 30 min, and Cx43 8-fold at 90 min. These high levels of mRNA expression were sustained for at least 4 h. In contrast, ramp flow was unable to significantly induce gene expression and even inhibited the activation of ERK1/ERK2. Step flow, which contains both a sharp temporal gradient in shear stress and a steady shear component, elicited only moderate and transient responses, indicating the distinct role of these fluid shear stimuli in endothelial signal transduction. The specific inhibitor of mitogen-activated protein kinase kinase PD-98059 inhibited impulse flow-induced c -fos and Cx43 mRNA expression. Thus these findings implicate the involvement of ERK1/ERK2, c -fos, and Cx43 in the signaling pathway induced by the temporal gradient in shear.

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The electro-deposition of silver on stationary and rotating glassy carbon discs

Canadian Journal of Chemistry ◽

10.1139/v77-572 ◽

1977 ◽

Vol 55 (23) ◽

pp. 4037-4044 ◽

Cited By ~ 6

Author(s):

Remigio Germano Barradas ◽

Stephen Fletcher ◽

Sandor Szabo

Keyword(s):

Experimental Data ◽

Mass Transport ◽

Glassy Carbon ◽

Quantitative Model ◽

Nucleation And Growth ◽

Experimental Conditions ◽

Electro Deposition ◽

Transport Effects ◽

Mass Transport Effects

The deposition of silver onto glassy carbon is described. The solution consisted of 10−2 M AgClO4 in 1.0 M HClO4. Experiments reveal the difficulties in trying to separate nucleation and growth phenomena from mass transport effects. A simple semi-quantitative model is proposed to explain the experimental data. It is also shown that the deposition reaction is not completely reversible under certain experimental conditions.

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