Journal: Arteriosclerosis, Thrombosis, and Vascular Biology
Article Title: Single-Cell and Spatial Transcriptomics Identified Fatty Acid–Binding Proteins Controlling Endothelial Glycolytic and Arterial Programming in Pulmonary Hypertension
doi: 10.1161/ATVBAHA.124.321173
Figure Lengend Snippet: HIF (hypoxia-inducible factor)-2α–mediated glycolysis induced by FABP (fatty acid–binding protein) 4/5 in pulmonary endothelial cells (ECs). A , A diagram showing the predicted transcription factors based on the DEGs and literature. B , Western blotting demonstrated HIF-2α but not p53 or c-Myc was upregulated in CKO lungs and normalized in TKO lungs. The β-actin on c-Myc blot was shared with Figure 1C FABP5. C , A representative heat map showed that glycolytic genes were dependent on HIF-2α using wild-type (WT), CKO mice, and Egln1 Tie2Cre /Hif2a Tie2Cre (EH2) mice. D , HIF-2α knockdown inhibited FABP4/5–induced endothelial proliferation. E , Nitrative stress assessed by protein nitrotyrosine modification was reduced in TKO lungs compared with CKO lungs. F , Overexpression of FABP4 and FABP5 promoted mitochondrial reactive oxygen species (ROS) levels in human pulmonary arterial EC (hPAECs). G , A diagram showing our proposed model. Our study addresses a novel role of lung endothelial FABP4/5 controlling PAEC accumulation through increased glycolysis in the pathogenesis of pulmonary arterial hypertension (PAH). By facilitating fatty acid uptake and translocation into mitochondria, FABP4/5 promote fatty acid oxidation (FAO) and ROS generation, which activates HIF-2α signaling to promote endothelial glycolysis. For 5-bromo-20-deoxyuridine (BrdU) assay in ( D ) and mitochondrial ROS assay in ( F ), each dot represents a biological replicate. The experiments were performed at least 3 times. ANOVA followed by Tukey post hoc analysis was used for statistical analysis ( B , D , E , and F ). Significance levels were denoted as P <0.05. α-NT indicates anti-nitrotyrosine; Adjp, adjusted P value; A.U., arbitrary unit; DAPI, 4',6-diamidino-2-phenylindole; DEG, differentially expressed gene; dNTP, deoxyribonucleotide triphosphate; ETO, etomoxir; 5-FU, 5-fluorouracil; siCTL, small interfering RNA control; siHIF, small interfering RNA targeting hypoxia-inducible factor; TF, transcription factor; and 2-DG, 2-deoxy-D-glucose.
Article Snippet: The normal human pulmonary arterial ECs (hPAECs) were purchased from Lonza (Alpharetta, GA).
Techniques: Binding Assay, Western Blot, Knockdown, Modification, Over Expression, Translocation Assay, BrdU Staining, ROS Assay, Small Interfering RNA, Control