Related Experiment Video
Updated: Jul 17, 2025
08:53
In Vitro Model Integrating Substrate Stiffness and Flow to Study Endothelial Cell Responses
Published on: July 19, 2024
545
Extracellular Matrix Stiffness Regulates Microvascular Stability by Controlling Endothelial Paracrine Signaling to
Yali Yu1,2,3, Yu Leng1,2, Xiuyue Song1,2
1Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, Medical College, Qingdao University, China (Y.Y., Y. Leng, X.S., J.M., L.M., L.Y., Y.Z., J.L., D.W.).
Arteriosclerosis, Thrombosis, and Vascular Biology
|August 31, 2023
Summary
Extracellular matrix (ECM) stiffness and TGFβ signaling cooperatively regulate microvascular stability. Stiff ECM promotes endothelial cell ITGB1 phosphorylation and CTGF secretion, inducing pericyte-myofibroblast differentiation and fibrosis.
Area of Science:
- Biomedical Engineering
- Cell Biology
- Tissue Engineering
Background:
- Pericyte differentiation into myofibroblasts drives fibrotic diseases by causing microvascular degeneration and ECM accumulation.
- Regulation of pericyte-myofibroblast differentiation within the microvascular niche remains unclear.
- A novel 2D co-culture platform for endothelial cells (ECs) and pericytes was previously established.
Purpose of the Study:
- To investigate the role of extracellular matrix (ECM) stiffness in regulating microvascular endothelial cells (ECs), pericytes, and their interactions.
- To elucidate the mechanisms underlying pericyte-myofibroblast differentiation in response to mechanical cues.
- To explore potential therapeutic targets for fibrotic diseases by understanding microvascular dynamics.
Main Methods:
- Primary microvessels were cultured on soft (≈6 kPa) or stiff ECM substrates.
- Immunostaining, RNA sequencing, RT-qPCR, Western blotting, and gene knockdown experiments were employed.
- Transforming growth factor beta (TGFβ) signaling inhibitor (A83-01) was used to modulate pathways.
Main Results:
- Stiff ECM induced pericyte differentiation into myofibroblasts (NG2+αSMA+), even with TGFβ inhibition.
- Soft ECM and TGFβ inhibition maintained microvascular stability and suppressed pericyte activation (NG2+αSMA-/low).
- Integrin β1 (Itgb1) was identified as a key mechanosensor; its knockdown inhibited myofibroblast differentiation.
- Endothelial cell ITGB1 phosphorylation (Y783) on stiff ECM promoted connective tissue growth factor (CTGF) secretion, inducing pericyte differentiation.
Conclusions:
- ECM stiffness and TGFβ signaling synergistically control microvascular stability and pericyte-myofibroblast differentiation.
- Stiff ECM enhances endothelial cell ITGB1 phosphorylation and CTGF release, driving fibrosis.
- Targeting ITGB1 and CTGF pathways may offer strategies to combat microvascular dysfunction in fibrotic conditions.
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