AMPK deficiency inhibits fatty acid oxidation in endothelial progenitor cells to aggravate impaired angiogenesis after ischemic stroke in hyperlipidemic mice.

Abstract

Background: Hyperlipidemia is a risk factor for stroke, and worsens neurological outcome after stroke. Endothelial progenitor cells (EPCs), which become dysfunctional in cerebral ischemia, hold capacity to promote revascularization.

Objective: We investigated the role of dyslipidemia in impairment of EPC-mediated angiogenesis in cerebral ischemic mice.

Methods and results: The high fat diet (HFD)-fed mice following by ischemic stroke exhibited increased infarct volumes and neurological severity scores, and poorer angiogenesis. Bone marrow-EPCs treated with palmitic acid (PA) showed impaired functions and inhibited activity of AMP-activated protein kinase (AMPK). Notably, AMPK deficiency aggravated EPC dysfunction, further decreased mitochondrial membrane potential, and increased reactive oxygen species level in EPCs with PA treatment. Furthermore, the expression of fatty acid oxidation (FAO)-related genes was remarkably reduced, and carnitine palmitoyltransferase 1A (CPT1A) protein expression was downregulated in AMPK-deficient EPCs. AMPK deficiency aggravated neurological severity scores and angiogenesis in ischemic brain of HFD-fed mice, accompanied by suppressed protein level of CPT1A. EPC transplantation corrected impaired neurological severity scores and angiogenesis in AMPK-deficient mice.

Conclusion: Our findings suggest that AMPK deficiency aggravates poor angiogenesis in ischemic brain by mediating FAO and oxidative stress thereby inducing EPC dysfunction in hyperlipidemic mice.