Human corneal stromal stem cells express anti-fibrotic microRNA-29a and 381-5p – A robust cell selection tool for stem cell therapy of corneal scarring
Yam, Gary Hin-Fai, Tianbing Yang, Moira L Geary, Mithun Santra, Martha Funderburgh, Elizabeth Rubin, Yiqin Du, Jose A Sahel, Vishal Jhanji, and James L Funderburgh. 2022. “Human Corneal Stromal Stem Cells Express Anti-Fibrotic MicroRNA-29a and 381-5p – a Robust Cell Selection Tool for Stem Cell Therapy of Corneal Scarring.” Journal of Advanced Research, May. https://doi.org/10.1016/j.jare.2022.05.008.
Corneal blindness due to scarring is treated with corneal transplantation. However, a global problem is the donor material shortage. Preclinical and clinical studies have shown that cell-based therapy using corneal stromal stem cells (CSSCs) suppresses corneal scarring, potentially mediated by specific microRNAs transported in extracellular vesicles (EVs). However, not every CSSC batch from donors achieves similar anti-scarring effects. Purpose
To examine miRNA profiles in EVs from human CSSCs showing “healing” versus “non-healing” effects on corneal scarring and to design a tool to select CSSCs with strong healing potency for clinical applications. Methods
Small RNAs from CSSC-EVs were extracted for Nanostring nCounter Human miRNA v3 assay. MicroRNAs expressed > 20 folds in “healing” EVs (P < 0.05) were subject to enriched gene ontology (GO) term analysis. MiRNA groups with predictive regulation on inflammatory and fibrotic signalling were studied by mimic transfection to (1) mouse macrophages (RAW264.7) for M1 phenotype assay; (2) human corneal keratocytes for cytokine-induced fibrosis, and (3) human CSSCs for corneal scar prevention in vivo. The expression of miR-29a was screened in additional CSSC batches and the anti-scarring effect of cells was validated in mouse corneal wounds. Results
Twenty-one miRNAs were significantly expressed in “healing” CSSC-EVs and 9 miRNA groups were predicted to associate with inflammatory and fibrotic responses, and tissue regeneration (P <10−6). Overexpression of miR-29a and 381-5p significantly prevented M1 phenotype transition in RAW264.7 cells after lipopolysaccharide treatment, suppressed transforming growth factor β1-induced fibrosis marker expression in keratocytes, and reduced scarring after corneal injury. High miR-29a expression in EV fractions distinguished human CSSCs with strong healing potency, which inhibited corneal scarring in vivo. Conclusion
We characterized the anti-inflammatory and fibrotic roles of miR-29a and 381-5p in CSSCs, contributing to scar prevention. MiR-29a expression in EVs distinguished CSSCs with anti-scarring quality, identifying good quality cells for a scarless corneal healing.View full article