Objective Vascular cells, particularly endothelial cells, adopt aerobic glycolysis to generate energy to support cellular functions. The effect of endothelial glycolysis on angiogenesis remains unclear. 6-Phosphofructo-2-kinase/fructose-2, 6-bisphosphatase, isoform 3 (PFKFB3), is a critical enzyme for endothelial glycolysis. By blocking or deleting PFKFB3 in endothelial cells, we investigated the influence of endothelial glycolysis on angiogenesis both in vitro and in vivo. Approach and Results Under hypoxic conditions or following treatment with angiogenic factors, endothelial PFKFB3 was upregulated both in vitro and in vivo. The knockdown or overexpression of PFKFB3 suppressed or accelerated endothelial proliferation and migration in vitro, respectively. Neonatal mice from a model of oxygen-induced retinopathy showed suppressed neovascular growth in the retina when endothelial PFKFB3 was genetically deleted or when the mice were treated with a PFKFB3 inhibitor. Additionally, tumors implanted in mice deficient in endothelial PFKFB3 grew more slowly and were provided with less blood flow. A lower level of phosphorylated AKT (pAKT) was observed in PFKFB3-knockdown endothelial cells, which was accompanied by a decrease in intracellular lactate. The addition of lactate to PFKFB3-knockdown cells rescued the suppression of endothelial proliferation and migration. Conclusions The blockade or deletion of endothelial PFKFB3 decreases angiogenesis both in vitro and in vivo. Thus, PFKFB3 is a promising target for the reduction of endothelial glycolysis and its related pathological angiogenesis.

Remote ischaemic conditioning (RIC) triggers endogenous protective pathways in distant organs such as the kidney, heart and brain, and represents an exciting new paradigm in neuroprotection. RIC involves repetitive inflation and deflation of a blood pressure cuff on the limb, and is safe and feasible. The exact mechanism of signal transmission from the periphery to the brain is not known, but both humoral factors and an intact nervous system seem to have critical roles. Early-phase clinical trials have already been conducted to test RIC in the prehospital setting in acute ischaemic stroke, and in subarachnoid haemorrhage for the prevention of delayed cerebral ischaemia. Furthermore, two small randomized clinical trials in patients with symptomatic intracranial atherosclerosis have shown that RIC can reduce recurrence of stroke and have neuroprotective activity. RIC represents a highly practical and translatable therapy for acute, subacute, and chronic neurological diseases with an ischaemic or inflammatory basis. In this Review, we consider the principles and mechanisms of RIC, evidence from preclinical models and clinical trials that RIC is beneficial in neurological disease, and how the procedure might be used in the future in disorders such as vascular cognitive impairment and traumatic brain injury.

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Experimental autoimmune encephalomyelitis (EAE) is a T cell-mediated autoimmune disease of the CNS. Metformin is the most widely used drug for diabetes and mediates its action via activating AMP-activated protein kinase (AMPK). We provide evidence that metformin attenuates the induction of EAE by restricting the infiltration of mononuclear cells into the CNS, down-regulating the expression of proinflammatory cytokines (IFN-γ, TNF-α, IL-6, IL-17, and inducible NO synthase (iNOS)), cell adhesion molecules, matrix metalloproteinase 9, and chemokine (RANTES). Furthermore, the AMPK activity and lipids alterations (total phospholipids and in free fatty acids) were restored by metformin treatment in the CNS of treated EAE animals, suggesting the possible involvement of AMPK. Metformin activated AMPK in macrophages and thereby inhibited biosynthesis of phospholipids as well as neutral lipids and also down-regulated the expression of endotoxin (LPS)-induced proinflammatory cytokines and their mediators (iNOS and cyclooxygenase 2). It also attenuated IFN-γ and IL-17-induced iNOS and cyclooxygenase 2 expression in RAW267.4 cells, further supporting its anti-inflammatory property. Metformin inhibited T cell-mediated immune responses including Ag-specific recall responses and production of Th1 or Th17 cytokines, while it induced the generation of IL-10 in spleen cells of treated EAE animals. Altogether these findings reveal that metformin may have a possible therapeutic value for the treatment of multiple sclerosis and other inflammatory diseases.