MicroRNA-21/PDCD4 Proapoptotic Signaling from Circulating CD341 Cells to Vascular Endothelial Cells: A Potential Contributor to Adverse Cardiovascular Outcomes in Patients with Critical Limb Ischemia

Abstract

OBJECTIVE In patients with type 2 diabetes (T2D) and critical limb ischemia (CLI), migration of circulating CD341 cells predicted cardiovascular mortality at 18 months after revascularization. This study aimed to provide long-term validation and mechanistic understanding of the biomarker. RESEARCH DESIGN AND METHODS The association between CD341 cell migration and cardiovascular mortality was reassessed at 6 years after revascularization. In a new series of T2D-CLI and control subjects, immuno-sorted bone marrow CD341 cells were profiled for miRNA expression and assessed for apoptosis and angiogenesis activity. The differentially regulatedmiRNA-21and its proapoptotic target, PDCD4,weretitrated to verify their contribution in transferring damaging signals from CD341 cells to endothelial cells. RESULTS Multivariable regression analysis confirmed that CD341 cell migration forecasts long-term cardiovascular mortality. CD341 cells from T2D-CLI patients were more apoptotic and less proangiogenic than those from control subjects and featured miRNA-21 downregulation, modulation of several long noncoding RNAs acting as miRNA-21 sponges, and upregulation of the miRNA-21 proapoptotic target PDCD4. Silencing miR-21 in control CD341 cells phenocopied the T2D-CLI cell behavior. In coculture, T2D-CLI CD341 cells imprinted naive endothelial cells, increasing apoptosis, reducing network formation, and modulating the TUG1 sponge/miRNA-21/PDCD4 axis. Silencing PDCD4 or scavenging reactive oxygen species protected endothelial cells from the negative influence of T2D-CLI CD341 cells. CONCLUSIONS Migration of CD341 cells predicts long-term cardiovascular mortality in T2D-CLI patients. An altered paracrine signaling conveys antiangiogenic and proapoptotic features from CD341 cells to the endothelium. This damaging interaction may increase the risk for life-threatening complications.