Related Experiment Video
Updated: Oct 25, 2025
Molecular Analysis of Endothelial-mesenchymal Transition Induced by Transforming Growth Factor-β Signaling
Published on: August 3, 2018
CD147 mediates the CD44s-dependent differentiation of myofibroblasts driven by transforming growth factor-β1
Emma L Woods1, Irina V Grigorieva1, Adam C Midgley1
1Wales Kidney Research Unit, Systems Immunity University Research Institute, Division of Infection and Immunity, College of Biomedical and Life Sciences, Cardiff University, Heath Park, Cardiff, United Kingdom.
Insights
Standard CD44s and CD147 interaction is crucial for myofibroblast differentiation and organ fibrosis. This study reveals their role in regulating mechanical tension for alpha-smooth muscle actin incorporation into stress fibers, impacting fibrotic progression.
Area of Science:
- Cell Biology
- Biochemistry
- Immunology
Background:
- Progressive organ fibrosis involves excessive extracellular matrix production, driven by factors like transforming growth factor-beta 1 (TGF-β1) and interleukin-1 beta (IL-1β).
- Hyaluronan (HA) and its receptor CD44 are central to fibrosis, but specific CD44 variants and their roles remain unclear.
- CD44 is essential for TGF-β1-induced myofibroblast differentiation and IL-1β-induced monocyte binding, with potential involvement of splice variants.
Purpose of the Study:
- To identify CD44 variants involved in TGF-β1 and IL-1β signaling in fibrosis.
- To investigate the profibrotic role of CD147 in the context of CD44 interactions.
- To elucidate the mechanism by which CD44 and CD147 regulate myofibroblast differentiation and function.
Main Methods:
- Immunocytochemistry and quantitative PCR to assess CD44 expression and function.
- Co-immunoprecipitation to determine protein-protein interactions between CD44 and CD147.
- siRNA-mediated knockdown of CD147 and confocal microscopy to analyze cellular responses.
- Collagen gel contraction assays to evaluate myofibroblast activity.
Main Results:
- Standard CD44s (CD44s) is essential for TGF-β1-induced fibroblast differentiation and IL-1β-induced monocyte binding.
- CD147 directly associates with CD44s, and this interaction is critical for myofibroblast differentiation.
- Absence of CD147 prevents alpha-smooth muscle actin (αSMA) incorporation into stress fibers and inhibits collagen gel contraction, indicating impaired myofibroblast function.
- Hyaluronan removal disrupts CD44s/CD147 colocalization at cell-cell contacts.
Conclusions:
- CD44s/CD147 colocalization is essential for regulating mechanical tension required for αSMA incorporation into F-actin stress fibers.
- This interaction plays a critical role in myofibroblast phenotype development and fibrotic progression.
- Targeting the CD44s/CD147 axis may offer a therapeutic strategy for organ fibrosis.
Abstract:
Progressive fibrosis leads to loss of organ function and affects many organs as a result of excessive extracellular matrix production. The ubiquitous matrix polysaccharide hyaluronan (HA) is central to this through association with its primary receptor, CD44, which exists as standard CD44 (CD44s) or multiple splice variants. Mediators such as profibrotic transforming growth factor (TGF)-β1 and proinflammatory interleukin (IL)-1β are widely associated with fibrotic progression. TGF-β1 induces myofibroblast differentiation, while IL-1β induces a proinflammatory fibroblast phenotype that promotes fibroblast binding to monocyte/macrophages. CD44 expression is essential for both responses. Potential CD44 splice variants involved, however, are unidentified. The TGF-β1-activated CD44/epidermal growth factor receptor complex induces differentiation of metastatic cells through interactions with the matrix metalloproteinase inducer, CD147. This study aimed to determine the CD44 variants involved in TGF-β1- and IL-1β-mediated responses and to investigate the potential profibrotic role of CD147. Using immunocytochemistry and quantitative PCR, standard CD44s were shown to be essential for both TGF-β1-induced fibroblast/myofibroblast differentiation and IL-1β-induced monocyte binding. Co-immunoprecipitation identified that CD147 associated with CD44s. Using CD147-siRNA and confocal microscopy, we also determined that incorporation of the myofibroblast marker, αSMA, into F-actin stress fibers was prevented in the absence of CD147 and myofibroblast-dependent collagen gel contraction was inhibited. CD147 did not associate with HA, but removal of HA prevented the association of CD44s with CD147 at points of cell-cell contact. Taken together, our data suggest that CD44s/CD147 colocalization is essential in regulating the mechanical tension required for the αSMA incorporation into F-actin stress fibers that regulates myofibroblast phenotype.
Related Concept Videos
01:16TGF - β Signaling Pathway
01:09Introduction to Fibroblasts
01:24Regulation of Angiogenesis and Blood Supply