Smooth muscle–derived progenitor cell myofibroblast differentiation through KLF4 downregulation promotes arterial remodeling and fibrosis
Sizhao Lu, … , Mark W. Majesky, Mary C.M. Weiser-Evans
Sizhao Lu, … , Mark W. Majesky, Mary C.M. Weiser-Evans
Published October 29, 2020
Citation Information: JCI Insight. 2020;5(23):e139445. https://doi.org/10.1172/jci.insight.139445.
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Research Article Stem cells Vascular biology

Smooth muscle–derived progenitor cell myofibroblast differentiation through KLF4 downregulation promotes arterial remodeling and fibrosis

Abstract

Resident vascular adventitial SCA1+ progenitor (AdvSca1) cells are essential in vascular development and injury. However, the heterogeneity of AdvSca1 cells presents a unique challenge in understanding signaling pathways orchestrating their behavior in homeostasis and injury responses. Using smooth muscle cell (SMC) lineage-tracing models, we identified a subpopulation of AdvSca1 cells (AdvSca1-SM) originating from mature SMCs that undergo reprogramming in situ and exhibit a multipotent phenotype. Here we employed lineage tracing and RNA-sequencing to define the signaling pathways regulating SMC-to-AdvSca1-SM cell reprogramming and AdvSca1-SM progenitor cell phenotype. Unbiased hierarchical clustering revealed that genes related to hedgehog/WNT/beta-catenin signaling were significantly enriched in AdvSca1-SM cells, emphasizing the importance of this signaling axis in the reprogramming event. Leveraging AdvSca1-SM–specific expression of GLI-Kruppel family member GLI1 (Gli1), we generated Gli1-CreERT2-ROSA26-YFP reporter mice to selectively track AdvSca1-SM cells. We demonstrated that physiologically relevant vascular injury or AdvSca1-SM cell–specific Kruppel-like factor 4 (Klf4) depletion facilitated the proliferation and differentiation of AdvSca1-SM cells to a profibrotic myofibroblast phenotype rather than macrophages. Surprisingly, AdvSca1-SM cells selectively contributed to adventitial remodeling and fibrosis but little to neointima formation. Together, these findings strongly support therapeutics aimed at preserving the AdvSca1-SM cell phenotype as a viable antifibrotic approach.

Authors

Sizhao Lu, Austin J. Jolly, Keith A. Strand, Allison M. Dubner, Marie F. Mutryn, Karen S. Moulton, Raphael A. Nemenoff, Mark W. Majesky, Mary C.M. Weiser-Evans

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Figure 2

AdvSca1-SM cells express 2 major classes of genes: genes related to hedgehog/WNT/beta-catenin signaling and ECM and ECM-modifying genes.

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AdvSca1-SM cells express 2 major classes of genes: genes related to hedg...
(A) Left: GSEA enrichment plot (top) and KEGG hedgehog signaling heatmap (bottom). GSEA tool was used to examine gene enrichment in AdvSca1-SM cells compared with mature SMCs and AdvSca1-MA cells. Right: Heatmap of levels of differentially expressed genes related to hedgehog and WNT signaling. Gene list was based on genes in the KEGG hedgehog signaling pathway (italicized pathway in Table 1). (B) Left: GSEA enrichment plot (top) and Reactome extracellular matrix organization heatmap (bottom). GSEA tool was used to examine gene enrichment in AdvSca1-SM cells compared with mature SMCs and AdvSca1-MA cells. Right: Heatmap of levels of differentially expressed genes related to ECM and ECM remodeling. Gene list was based on consensus of genes in the top-ranking ECM-related pathways (Reactome: extracellular matrix organization, collagen formation, degradation of the extracellular matrix, and collagen biosynthesis and modifying enzymes; bold pathways in Table 1). For GSEA heatmaps, red indicates upregulated genes, and blue indicates downregulated genes. For pathway analysis heatmaps, red indicates upregulated genes, and green indicates downregulated genes.