Abstract 16970: Acetyl-CoA Metabolism: A Catalyst for Improved Vascular Recovery in Limb Ischemia via Transdifferentiation Mechanisms

Abstract

Background: Angiogenic transdifferentiation, the process by which resident fibroblasts transform into endothelial cells, contributes to restoring perfusion and preserving ischemic tissue. The metabolic shift is essential for transdifferentiation in vitro. Acetyl-CoA, a metabolite involved in histone acetylation, is a key substrate, and ATP Citrate Lyase (ACL) is the enzyme responsible for converting citrate to acetyl-CoA. We hypothesized that acetyl-CoA metabolism may regulate vascular recovery in limb ischemia through angiogenic transdifferentiation. Methods: We employed in vivo Matrigel plug assays, a murine hindlimb ischemia model, fibroblast lineage tracing mice, and ACL fibroblast-specific knockout mice to investigate the function of acetyl-CoA in vascular recovery and transdifferentiation. Isotope tracing assays were conducted to identify the primary carbon sources of acetyl-CoA during transdifferentiation, and pharmacological interventions targeting the corresponding transporters were used to confirm the findings. Results: In our hindlimb ischemia model, we observed a significant increase in ACL expression, particularly in fibroblasts, in the ischemic tissue on day 3 after surgery, coinciding with the peak of vascular flow recovery. Subcutaneous administration of Matrigel in mice revealed that ACL knockdown in fibroblasts reduced plug vascularity and the number of induced endothelial cells. Furthermore, both pharmacological inhibition of global ACL expression and genetic suppression of ACL in fibroblasts significantly impaired limb vascular recovery following ischemia. Importantly, inhibition of ACL in lineage-tracing mice resulted in a significant reduction in the population of induced endothelial cells, indicating that ACL ablation in fibroblasts blocked angiogenic transdifferentiation. In addition, we demonstrated that glucose and glutamine were the primary carbon sources for accumulated acetyl-CoA, and inhibition of glucose transporter (Glut1) or glutamine transporter (Slc1a5) significantly impaired transdifferentiation. Conclusions: Acetyl-CoA accumulation through ACL-mediated metabolism improves vascular recovery in limb ischemia by promoting angiogenic transdifferentiation.