CD34 PI16 fibroblast progenitors aggravate neointimal lesions of allograft arteries via CCL11/CCR3-PI3K/AKT pathway.

Transplant-accelerated arteriosclerosis is a common complication that limits the long-term survival of organ transplant recipients. While previous studies have indicated the involvement of CD34 stem/progenitor cells (SPCs) in this process, their heterogeneity and potential adverse effects remains incompletely understood. To investigate the role of CD34 SPCs in transplant arteriosclerosis, we used various genetically modified mouse models, including BALB/c, C57BL/6J, CD34-CreER, Rosa26-tdTomato, Rosa26-iDTR, CD34-Dre, PI16-CreER, and CAG-LSL-RSR-tdTomato-2A-DTR mice. Single-cell RNA sequencing (scRNA-seq), chemokine antibody microarrays, ELISA assays, and immunohistochemistry were employed to identify fibroblast progenitors and their interactions with smooth muscle cells. Furthermore, and experiments targeting the CCL11/CCR3-PI3K/AKT signaling pathway were conducted to assess its role in the pathogenesis of transplant arteriosclerosis. Single-cell RNA-seq and genetic lineage tracing revealed a subpopulation of fibroblast progenitors, characterized by high CD34 and PI16 expression, which differentiated into a distinct chemotactic fibroblast subset. Proteomic and scRNA analysis revealed that this CD34 PI16 subgroup released CCL11 (Eotaxin-1), which promoted intimal hyperplasia through the paracrine activation of smooth muscle cells. Binding of CCL11 to its receptor CCR3 activated the PI3K/AKT signaling pathway in smooth muscle cells, driving their proliferation and migration. , overexpression of CCL11 promoted neointimal hyperplasia, while neutralizing CCL11 or inhibiting CCR3 alleviated neointimal formation. These findings identified CD34 PI16 fibroblast progenitors that differentiate into specific chemotactic fibroblasts, releasing chemokines pivotal for neointima formation, suggesting a therapeutic strategy targeting their chemotactic activity.