PLX044573

GSE145569: Smooth muscle cell-derived vascular progenitor cells promote arterial remodeling and fibrosis through loss of Klf4 activity and spontaneous differentiation into myofibroblasts

• Organsim mouse
• Type RNASEQ
• Target gene
• Project ARCHS4

Resident vascular adventitial progenitor cells express the stem cell marker, Sca1 (AdvSca1 cells). Using smooth muscle cell (SMC) lineage tracing models, we identified a subpopulation of AdvSca1 cells (AdvSca1-SM) that originate from mature SMCs that undergo reprogramming in situ and exhibit a multipotent phenotype. The adventitial microenvironment and induction of the transcription factor, Klf4 is critical to reprogramming; however, the mechanism of Klf4 induction is unknown. We aimed to define the signaling pathways involved in SMC reprogramming and the fate of AdvSca1-SM cells in response to vascular injury. Flow sorting was used to isolate YFP+Sca1- SMCs, YFP+Sca1+ AdvSca1-SM cells, and YFP-Sca1+ non-SMC-derived AdvSca1 cells from aortae (AO) and carotid arteries (CA) of SMC YFP reporter mice. RNA-seq analysis and unbiased hierarchical clustering revealed that genes related to hedgehog/Wnt/-catenin signaling are significantly enriched in AdvSca1-SM cells, emphasizing the importance of this signaling axis in SMC reprogramming. CA injury was induced by ligating the left common CA of SMC YFP reporter mice. In response to injury, AdvSca1-SM cells downregulate genes in the hedgehog/Wnt/beta-catenin signaling pathway, as well as stemness-related genes, and adopt a myofibroblast-like phenotype. To selectively fate-map AdvSca1-SM cells, we took advantage of the selective expression of Gli1 by AdvSca1-SM cells and generated Gli1-CreERT2-Rosa26-YFP reporter mice. Immunofluorescent (IF) staining show that YFP was expressed exclusively in a subpopulation of adventitial Sca1-positive cells. RNA-seq confirmed YFP+Sca1+ cell population in SMC and Gli1 lineage tracing models exhibit a highly similar gene expression profile, supporting this model to faithfully track AdvSca1-SM cells. CA injury induced proliferation and differentiation of AdvSca1-SM cells to myofibroblasts rather than macrophages, as indicated by IF stainings and flow cytometry. Surprisingly, AdvSca1-SM cells selectively contributed to adventitial remodeling and fibrosis, but little neointima formation. AdvSca1-SM cell specific genetic knockout of Klf4 induced spontaneous differentiation and expansion of AdvSca1-SM cells and increased perivascular fibrosis. SOURCE: Mary,C.M.,Weiser-Evans (Mary.weiser@ucdenver.edu) - Dr. Mary C.M. Weiser-Evans University of Colorado Anschutz Medical Campus