Secretome of Mesenchymal Stromal Cells Prevents Myofibroblasts Differentiation by Transferring Fibrosis-Associated microRNAs within Extracellular Vesicles

Abstract

Fibroblasts differentiation into myofibroblasts is a central event of tissue fibrosis. Multipotent mesenchymal stromal cells (MSCs) secretome can interfere with fibrosis development; despite precise underlying mechanisms remain unclear. In this study, we tested the hypothesis that MSC secretome can affect fibroblast’ differentiation into myofibroblasts by delivering regulatory RNAs, including microRNAs to these cells. Using the model of transforming growth factor-beta (TGFbeta)-induced fibroblast differentiation into myofibroblasts, we tested the activity of human MSC secretome components, specifically extracellular vesicles (MSC-EV). We showed that MSC-EV down-regulated secretion of extracellular matrix proteins by fibroblasts as well as suppressed their contractility resulting in prevention as well as reversion of fibroblasts differentiation to myofibroblasts. High-throughput sequencing of RNAs extracted from MSC-EV has revealed many fibrosis-associated microRNAs. Fibroblast treatment with MSC-EV led to direct transfer of microRNAs, which resulted in the elevation of most prominent fibrosis-associated microRNAs, including microRNA-21 and microRNA-29c. Using MSC-EV transfection by antagomirs to these microRNAs we demonstrated their involvement in the suppression of fibroblast differentiation in our model. Taken together, MSC secretome can suppress fibrosis by prevention of fibroblast differentiation into myofibroblasts as well as induce de-differentiation of the latter by direct transfer of specific microRNAs.

Mesenchymal Stromal Cells as Critical Contributors to Tissue Regeneration

“…Noteworthy, any fibroblast could fit in MSC definition, however, the relationship between phenotype and cell function may be ambiguous. Thus, we and others have demonstrated in some studies the substantial differences in regenerative effects of so-called MSCs and so-called fibroblasts (Gatti et al, 2011;Basalova et al, 2020).…”

“…In addition to the secretion of individual paracrine factors, MSCs can secrete EV, mostly exosomes (Basalova et al, 2020 ), whose composition also varies depending on external signals (Lopatina et al, 2014 ). The significance of this cell communication mechanism is crucial because MSCs can transmit molecules of various nature, including proteins, lipids, and nucleic acids such as mRNA and regulatory non-coding RNAs, within EV to target cells (Kalinina et al, 2015b ; Yáñez-Mó et al, 2015 ; Efimenko et al, 2016 ; Basalova et al, 2020 ). Due to the possible targeted effects of EV, their transfer to nearby cells can help fine-tune the effects of the MSC secretome (Hoshino et al, 2015 ).…”

“…The EV secreted by MSCs can also contribute to tissue regeneration due to their effect on the microenvironment. In particular, studies have demonstrated that they contain micrornas that suppress the formation of myofibroblasts and, accordingly, the development of fibrosis by suppressing the TGF-beta2/SMAD2 pathway and the production of ECM proteins (Fang et al, 2016 ; Basalova et al, 2020 ).…”

Tear-Derived Exosome Proteins Are Increased in Patients with Thyroid Eye Disease

“…Increased MMP-9 and CH13L1 levels in exosomes, and extracellular matrix modulating and fibrosis-promoting exosomal activity may play especially important roles in TED, as orbital tissue remodeling and fibrosis are integral parts of the disease mechanism. Previous reports showed that nuclear Sp1 protein is more abundant in orbital fibroblasts, and its binding to specific sites on DNA is greater than regular fibroblasts to modulate cytokine response [ 43 , 44 ]. Moreover, SP1 was shown to be the main target of delivered miRs in leukemic [ 45 ] and other cancer models [ 46 ].…”

Mesenchymal Stem Cells and Their Extracellular Vesicles: A Potential Game Changer for the COVID-19 Crisis

“…Like their parent cells, exosomes have been reported to stimulate cellular regeneration, functional recovery in various pathological conditions ( Derkus et al, 2017 ). Moreover, recently MSC-derived EVs have been reported to suppress fibrosis by preventing differentiation of fibroblasts into myofibroblasts ( Basalova et al, 2020 ).…”