2 research outputs found
Pentose Pathway Activation Is Superior to Increased Glycolysis for Therapeutic Angiogenesis in Peripheral Arterial Disease
Background In endothelial cells (ECs), glycolysis, regulated by PFKFB3 (6âphosphofructoâ2âkinase/fructoseâ2,6âbiphosphatase, isoformâ3), is the major metabolic pathway for ATP generation. In preclinical peripheral artery disease models, VEGF165a (vascular endothelial growth factor165a) and microRNAâ93 both promote angiogenesis. Methods and Results Mice following hindâlimb ischemia (HLI) and ECs with, and without, hypoxia and serum starvation were examined with, and without, microRNAâ93 and VEGF165a. PostâHLI perfusion recovery was monitored. EC metabolism was studied using seahorse assay, and the expression and activity of major metabolism genes were assessed. Reactive oxygen species levels and EC permeability were evaluated. C57Bl/6J mice generated a robust angiogenic response to HLI, with ECs from ischemic versus nonischemic muscle demonstrating no increase in glycolysis. Balb/CJ mice generated a poor angiogenic response postâHLI; ischemic versus nonischemic ECs demonstrated significant increase in glycolysis. MicroRNAâ93âtreated Balb/CJ mice postâHLI showed better perfusion recovery, with ischemic versus nonischemic ECs showing no increase in glycolysis. VEGF165aâtreated Balb/CJ mice postâHLI showed no improvement in perfusion recovery with ischemic versus nonischemic ECs showing significant increase in glycolysis. ECs under hypoxia and serum starvation upregulated PFKFB3. In ECs under hypoxia and serum starvation, VEGF165a versus control significantly upregulated PFKFB3 and glycolysis, whereas miRâ93 versus control demonstrated no increase in PFKFB3 or glycolysis. MicroRNAâ93 versus VEGF165a upregulated glucoseâ6âphosphate dehydrogenase expression and activity, activating the pentose phosphate pathway. MicroRNAâ93 versus control increased reduced nicotinamide adenine dinucleotide phosphate and virtually eliminated the increase in reactive oxygen species. In ECs under hypoxia and serum starvation, VEGF165a significantly increased and miRâ93 decreased EC permeability. Conclusions In peripheral artery disease, activation of the pentose phosphate pathway to promote angiogenesis may offer potential therapeutic advantages
Homocysteine Induces Inflammation in Retina and Brain
Homocysteine (Hcy) is an amino acid that requires vitamins B12 and folic acid for its metabolism. Vitamins B12 and folic acid deficiencies lead to hyperhomocysteinemia (HHcy, elevated Hcy), which is linked to the development of diabetic retinopathy (DR), age-related macular degeneration (AMD), and Alzheimer’s disease (AD). The goal of the current study was to explore inflammation as an underlying mechanism of HHcy-induced pathology in age related diseases such as AMD, DR, and AD. Mice with HHcy due to a lack of the enzyme cystathionine-β-synthase (CBS) and wild-type mice were evaluated for microglia activation and inflammatory markers using immuno-fluorescence (IF). Tissue lysates isolated from the brain hippocampal area from mice with HHcy were evaluated for inflammatory cytokines using the multiplex assay. Human retinal endothelial cells, retinal pigment epithelial cells, and monocyte cell lines treated with/without Hcy were evaluated for inflammatory cytokines and NFκB activation using the multiplex assay, western blot analysis, and IF. HHcy induced inflammatory responses in mouse brain, retina, cultured retinal, and microglial cells. NFκB was activated and cytokine array analysis showed marked increase in pro-inflammatory cytokines and downregulation of anti-inflammatory cytokines. Therefore, elimination of excess Hcy or reduction of inflammation is a promising intervention for mitigating damage associated with HHcy in aging diseases such as DR, AMD, and AD