RESUMO
Angiogenesis, the growth of new blood vessels from pre-existing vasculature, is essential for the development of new organ systems, but transcriptional control of angiogenesis remains incompletely understood. Here we show that FOXC1 is essential for retinal angiogenesis. Endothelial cell (EC)-specific loss of Foxc1 impairs retinal vascular growth and expression of Slc3a2 and Slc7a5, which encode the heterodimeric CD98 (LAT1/4F2hc) amino acid transporter and regulate the intracellular transport of essential amino acids and activation of the mammalian target of rapamycin (mTOR). EC-Foxc1 deficiency diminishes mTOR activity, while administration of the mTOR agonist MHY-1485 rescues perturbed retinal angiogenesis. EC-Foxc1 expression is required for retinal revascularization and resolution of neovascular tufts in a model of oxygen-induced retinopathy. Foxc1 is also indispensable for pericytes, a critical component of the blood-retina barrier during retinal angiogenesis. Our findings establish FOXC1 as a crucial regulator of retinal vessels and identify therapeutic targets for treating retinal vascular disease.
Assuntos
Barreira Hematorretiniana , Células Endoteliais , Fatores de Transcrição Forkhead , Neovascularização Retiniana , Animais , Masculino , Camundongos , Angiogênese , Barreira Hematorretiniana/metabolismo , Células Endoteliais/metabolismo , Fatores de Transcrição Forkhead/metabolismo , Fatores de Transcrição Forkhead/genética , Cadeia Pesada da Proteína-1 Reguladora de Fusão/metabolismo , Cadeia Pesada da Proteína-1 Reguladora de Fusão/genética , Transportador 1 de Aminoácidos Neutros Grandes/metabolismo , Transportador 1 de Aminoácidos Neutros Grandes/genética , Camundongos Endogâmicos C57BL , Camundongos Knockout , Pericitos/metabolismo , Retina/metabolismo , Neovascularização Retiniana/metabolismo , Neovascularização Retiniana/genética , Neovascularização Retiniana/patologia , Vasos Retinianos/metabolismo , Serina-Treonina Quinases TOR/metabolismoRESUMO
Pro-coagulant, anti-coagulant and fibrinolytic pathways are responsible for maintaining hemostatic balance under physiological conditions. Any deviation from these pathways would result in hypercoagulability leading to life threatening diseases like myocardial infarction, stroke, portal vein thrombosis, deep vein thrombosis (DVT) and pulmonary embolism (PE). Angiogenesis is the process of sprouting of new blood vessels from pre-existing ones and plays a critical role in vascular repair, diabetic retinopathy, chronic inflammation and cancer progression. Serpins; a superfamily of protease inhibitors, play a key role in regulating both angiogenesis and coagulation. They are characterized by the presence of highly conserved secondary structure comprising of 3 ß-sheets and 7-9 α-helices. Inhibitory role of serpins is modulated by binding to cofactors, specially heparin and heparan sulfate proteoglycans (HSPGs) present on cell surfaces and extracellular matrix. Heparin and HSPGs are the mainstay of anti-coagulant therapy and also have therapeutic potential as anti-angiogenic inhibitors. Many of the heparin binding serpins that regulate coagulation cascade are also potent inhibitors of angiogenesis. Understanding the molecular mechanism of the switch between their specific anti-coagulant and anti-angiogenic role during inflammation, stress and regular hemostasis is important. In this review, we have tried to integrate the role of different serpins, their interaction with cofactors and their interplay in regulating coagulation and angiogenesis.