Multilineage commitment of Sca-1⁺ cells in reshaping vein grafts

Abstract

Vein graft failure remains a significant clinical problem. Similar to other vascular diseases, stenosis of vein grafts is caused by several cell lines; however, the sources of these cells remain unclear. The objective of this study was to investigate the cellular sources that reshape vein grafts. By analyzing transcriptomics data and constructing inducible lineage-tracing mouse models, we investigated the cellular components of vein grafts and their fates. The sc-RNAseq data suggested that Sca-1+ cells were vital players in vein grafts and might serve as progenitors for multilineage commitment. By generating a vein graft model in which the venae cavae from C57BL/6J wild-type mice were transplanted adjacent to the carotid arteries of Sca-1(Ly6a)-CreERT2; Rosa26-tdTomato mice, we demonstrated that the recipient Sca-1+ cells dominated reendothelialization and the formation of adventitial microvessels, especially at the perianastomotic regions. In turn, using chimeric mouse models, we confirmed that the Sca-1+ cells that participated in reendothelialization and the formation of adventitial microvessels all had a non-bone-marrow origin, whereas bone-marrow-derived Sca-1+ cells differentiated into inflammatory cells in vein grafts. Furthermore, using a parabiosis mouse model, we confirmed that non-bone-marrow-derived circulatory Sca-1+ cells were vital for the formation of adventitial microvessels, whereas Sca-1+ cells derived from local carotid arteries were the source of endothelium restoration. Using another mouse model in which venae cavae from Sca-1 (Ly6a)-CreERT2; Rosa26-tdTomato mice were transplanted adjacent to the carotid arteries of C57BL/6J wild-type mice, we confirmed that the donor Sca-1+ cells were mainly responsible for smooth muscle cells commitment in the neointima, particularly at the middle bodies of vein grafts. In addition, we provided evidence that knockdown/knockout of Pdgfrα in Sca-1+ cells decreased the cell potential to generate SMCs in vitro and decreased number of intimal SMCs in vein grafts. Our findings provided cell atlases of vein grafts, which demonstrated that recipient carotid arteries, donor veins, non-bone-marrow circulation, and the bone marrow provided diverse Sca-1+ cells/progenitors that participated in the reshaping of vein grafts.

Stem cell antigen-1+cell-derived fibroblasts are crucial for cardiac fibrosis during heart failure

“…Secondly, we were concerned primarily broblasts that differentiated from Sca1 + cells, and might be lacking of deep exploration in the differentiation of other cell types. Thirdly, Sca1 expressed only in mice and not on human [51], which inevitably limited our results to extrapolate to human, therefore, it is necessary a further exploration on other MSC and cardiac progenitor/stem cell biomarkers such as c-Kit, Gli1 [43]. Fourthly, the method of cardiac function evaluation was limited.…”

“…Sca1 is reported to be expressed in various tissues, including fat deposits, adventitial and endothelial cells of arteries, bone marrow, skeletal muscle, heart, and other tissue/organ systems [16,42]. It is known that Sca1 + cells can also differentiate into endothelial when vessel injury [20,43] and smooth muscle cells after severe vessel injury [44]. We therefore investigated whether other cell types derived from Sca1 + cells play a role in cardiac brosis using a pressure overload model.…”