| AGGF1?Angiogenic factor with G-patch and FHA domain1?is the first gene identified and reported for Klippel–Trénaunay syndrome?KTS?.AGGF1 is located on chromosome 5q13.3 and encodes a new angiogenic factor.AGGF1 protein contains 714amino acids and has 4 known functional domains,including the coiled coil domain and OCRE domain at the N-terminus,and the FHA?Forkhead-associated domain?domain and G-patch domain at the C-terminus.AGGF1 encodes a strong angiogenic factor that promotes endothelial cell proliferation,and capillary tube formartion.In vivo,chick chorioallantoic membrane angiogenic assays showed that the recombinant AGGF1 protein can stimulate angiogenesis as strongly as VEGFA,and intramuscular administration of an AGGF1 expression plasmid can effectively promote therapeutic angiogenesis,and improve blood perfusion in a mouse hindlimb ischemia model.Zebra fish studies indicated that AGGF1 is required for specification of vein and hemangioblasts,which are multi-potenty progenitor cells that can differentiate into endothelial cells and all types of blood cells.AGGF1 can successfully treat CAD and MI,and AGGF1 is much more better than VEGFA due to its inhibition function on vascular permeability.Recent studies also showed that AGGF1 supresses neointimal formation after vascular injury efficiently.This indicates that AGGF1 protein therapy maybe an alternative effective strategy to treat restenosis after revascularization therapies of atherosclerosis,CAD and MI.Diabetes mellitus?DM?is a type of common metabolic disorders with high blood sugar levels over a prolonged period and numerous complications,including peripheral vascular disease?PAD?,cardiovascular disease,cerebral vascular disease,diabetic ketoacidosis,chronic kidney disease,diabetic ketoacidosis,hyperosmolar hyperglycemic state and eyes damage.DM is associated with dysregulation of vascular endothelial cells and affects over 400 million people worldwide.Vascular complications in diabetes mellitus are associated with dysregulation of vascular remodeling,vascular growth,and impaired responsiveness to oxidative stress,abnormal endothelial regeneration and angiogenesis.Thus,there is an urgent clinic need to develop therapeutic interventions aimed at improving the repair of dysfunctional endothelium and restoring blood flow in diabetic patients.Endothelial progenitor cells?EPCs?are progenitors of endothelial cells and have the potential to proliferate and differentiate to form perfused blood vessels in vivo and tube-like structures in vitro.EPCs are dysfunctional under diabetes mellitus condition resulting in impaired postischemic reparative neovascularization.Recently,accumulating data showed that EPCs are robustly effective in vascular injury repairment and blood perfusion.Thus,we hypothesized that AGGF1 may be related to dysfunction of EPCs in type 2 diabetes mellitus and try to reveal the underlying mechanisms connecting EPCs function and AGGF1 expression,hoping to provide significant foundation for AGGF1-EPCs therapy of diabetic vascular diseases,also a paradigm for AGGF1-EPCs therapy of other cerebrovascular disease and cardiovascular diseases.We focused on angiogenic factor AGGF1 and elucidate its potential role in EPCs and EPCs-medaited therapy for diabetic hindlimb ischemia.We found that EPCs from high fat diet?HFD?-induced diabetic mice showed impaired tube formation,proliferation,transendothelial migration and migration.EPCs from Aggf1+/-or Aggf1+/-db/db mice also showed impaired tube formation,proliferation,transendothelial migration and migration.The data suggest that AGGF1 is involved in EPC functions.In wild type mouse EPCs,tube formation,porliferation,transendothelial migration and migration were significantly reduced upon high glucose treatment,however,the damaging effects of high glucose were markedly reversed by AGGF1 pretreatment of EPCs.The ROS levels produced by high glucose treatment were significantly reduced by treatment with AGGF1.Therapeutically,AGGF1-pretreated EPCs improved the angiogenesis and blood perfusion in the hindlimb ischemia models of HFD-induced diabetes mellitus mice.The data indicate that AGGF1may be developed into a therapeutic tool for EPCs-based cell therapy of diabetes-associated vascular complications.We also found that AGGF1-primed EPCs can successfully treat vascular complications associated with hindlimb ischemia in a genetics diabetic model in db/db mice.Mechanistic studies suggested that high glucose increased nuclear accumulation of Fyn,and subsequently decreased the nuclear localization of nuclear factor?erythroidderived 2?-like 2?nNrf2?,suppressing Nrf2 downstream target genes heme oxygenase-1?HO-1?,NAD?P?H dehydrogenase?quinone1,NQO-1?and catalase?CAT?,and impaire antioxidant capacity of EPCs.However,AGGF1 reduced nuclear accumulation of Fyn,and subsequently increased the nuclear localization of nuclear factor?erythroidderived 2?-like 2?nNrf2?,promoting the expression of Nrf2downstream target genes heme oxygenase-1?HO-1?,NAD?P?H dehydrogenase?quinone1,NQO-1?and catalase?CAT?,which improved the antioxidant capacity of EPCs.The data suggest that the damaging effects of oxidant stress were obviously blunted by treatment with AGGF1.Furthermore,the existence of PI3K inhibitor?Wartmannin?robustly prohibited the AGGF1 rescue function of HG-induced oxidative stress.Moreover,Akt or Nrf2 knockdown almost completely counteracted the protective effects of AGGF1 on EPCs function in vitro.Taken together,our data showed that:?1?AGGF1 is required for angiogenic function of EPCs;?2?AGGF1 increases EPCs resistance to diabetes mellitus–induced oxidative stress damage;?3?AGGF1 improves therapeutic efficacy of EPCs in treating diabetic hindlimb ischemia in mice;?4?AGGF1 regulates pAkt/Fyn/Nrf2 signal pathway,and blocks diabetes mellitus-induced EPCs dysfunction;?5?AGGF1 Provides a new effective paradigm for treatment of diabetic vascular diseases for the first time. |
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