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Redirecting Valvular Myofibroblasts into Dormant Fibroblasts through Light-mediated Reduction in Substrate Modulus

Fibroblasts residing in connective tissues throughout the body are responsible for extracellular matrix (ECM) homeostasis and repair. In response to tissue damage, they activate to become myofibroblasts, which have organized contractile cytoskeletons and produce a myriad of proteins for ECM remodeli...

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Autores principales: Wang, Huan, Haeger, Sarah M., Kloxin, April M., Leinwand, Leslie A., Anseth, Kristi S.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2012
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3396623/
https://www.ncbi.nlm.nih.gov/pubmed/22808079
http://dx.doi.org/10.1371/journal.pone.0039969
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author Wang, Huan
Haeger, Sarah M.
Kloxin, April M.
Leinwand, Leslie A.
Anseth, Kristi S.
author_facet Wang, Huan
Haeger, Sarah M.
Kloxin, April M.
Leinwand, Leslie A.
Anseth, Kristi S.
author_sort Wang, Huan
collection PubMed
description Fibroblasts residing in connective tissues throughout the body are responsible for extracellular matrix (ECM) homeostasis and repair. In response to tissue damage, they activate to become myofibroblasts, which have organized contractile cytoskeletons and produce a myriad of proteins for ECM remodeling. However, persistence of myofibroblasts can lead to fibrosis with excessive collagen deposition and tissue stiffening. Thus, understanding which signals regulate de-activation of myofibroblasts during normal tissue repair is critical. Substrate modulus has recently been shown to regulate fibrogenic properties, proliferation and apoptosis of fibroblasts isolated from different organs. However, few studies track the cellular responses of fibroblasts to dynamic changes in the microenvironmental modulus. Here, we utilized a light-responsive hydrogel system to probe the fate of valvular myofibroblasts when the Young’s modulus of the substrate was reduced from ∼32 kPa, mimicking pre-calcified diseased tissue, to ∼7 kPa, mimicking healthy cardiac valve fibrosa. After softening the substrata, valvular myofibroblasts de-activated with decreases in α-smooth muscle actin (α-SMA) stress fibers and proliferation, indicating a dormant fibroblast state. Gene signatures of myofibroblasts (including α-SMA and connective tissue growth factor (CTGF)) were significantly down-regulated to fibroblast levels within 6 hours of in situ substrate elasticity reduction while a general fibroblast gene vimentin was not changed. Additionally, the de-activated fibroblasts were in a reversible state and could be re-activated to enter cell cycle by growth stimulation and to express fibrogenic genes, such as CTGF, collagen 1A1 and fibronectin 1, in response to TGF-β1. Our data suggest that lowering substrate modulus can serve as a cue to down-regulate the valvular myofibroblast phenotype resulting in a predominantly quiescent fibroblast population. These results provide insight in designing hydrogel substrates with physiologically relevant stiffness to dynamically redirect cell fate in vitro.
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spelling pubmed-33966232012-07-17 Redirecting Valvular Myofibroblasts into Dormant Fibroblasts through Light-mediated Reduction in Substrate Modulus Wang, Huan Haeger, Sarah M. Kloxin, April M. Leinwand, Leslie A. Anseth, Kristi S. PLoS One Research Article Fibroblasts residing in connective tissues throughout the body are responsible for extracellular matrix (ECM) homeostasis and repair. In response to tissue damage, they activate to become myofibroblasts, which have organized contractile cytoskeletons and produce a myriad of proteins for ECM remodeling. However, persistence of myofibroblasts can lead to fibrosis with excessive collagen deposition and tissue stiffening. Thus, understanding which signals regulate de-activation of myofibroblasts during normal tissue repair is critical. Substrate modulus has recently been shown to regulate fibrogenic properties, proliferation and apoptosis of fibroblasts isolated from different organs. However, few studies track the cellular responses of fibroblasts to dynamic changes in the microenvironmental modulus. Here, we utilized a light-responsive hydrogel system to probe the fate of valvular myofibroblasts when the Young’s modulus of the substrate was reduced from ∼32 kPa, mimicking pre-calcified diseased tissue, to ∼7 kPa, mimicking healthy cardiac valve fibrosa. After softening the substrata, valvular myofibroblasts de-activated with decreases in α-smooth muscle actin (α-SMA) stress fibers and proliferation, indicating a dormant fibroblast state. Gene signatures of myofibroblasts (including α-SMA and connective tissue growth factor (CTGF)) were significantly down-regulated to fibroblast levels within 6 hours of in situ substrate elasticity reduction while a general fibroblast gene vimentin was not changed. Additionally, the de-activated fibroblasts were in a reversible state and could be re-activated to enter cell cycle by growth stimulation and to express fibrogenic genes, such as CTGF, collagen 1A1 and fibronectin 1, in response to TGF-β1. Our data suggest that lowering substrate modulus can serve as a cue to down-regulate the valvular myofibroblast phenotype resulting in a predominantly quiescent fibroblast population. These results provide insight in designing hydrogel substrates with physiologically relevant stiffness to dynamically redirect cell fate in vitro. Public Library of Science 2012-07-13 /pmc/articles/PMC3396623/ /pubmed/22808079 http://dx.doi.org/10.1371/journal.pone.0039969 Text en Wang et al. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Wang, Huan
Haeger, Sarah M.
Kloxin, April M.
Leinwand, Leslie A.
Anseth, Kristi S.
Redirecting Valvular Myofibroblasts into Dormant Fibroblasts through Light-mediated Reduction in Substrate Modulus
title Redirecting Valvular Myofibroblasts into Dormant Fibroblasts through Light-mediated Reduction in Substrate Modulus
title_full Redirecting Valvular Myofibroblasts into Dormant Fibroblasts through Light-mediated Reduction in Substrate Modulus
title_fullStr Redirecting Valvular Myofibroblasts into Dormant Fibroblasts through Light-mediated Reduction in Substrate Modulus
title_full_unstemmed Redirecting Valvular Myofibroblasts into Dormant Fibroblasts through Light-mediated Reduction in Substrate Modulus
title_short Redirecting Valvular Myofibroblasts into Dormant Fibroblasts through Light-mediated Reduction in Substrate Modulus
title_sort redirecting valvular myofibroblasts into dormant fibroblasts through light-mediated reduction in substrate modulus
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3396623/
https://www.ncbi.nlm.nih.gov/pubmed/22808079
http://dx.doi.org/10.1371/journal.pone.0039969
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