title: β1 -adrenergic receptor autoantibodies from heart failure patients enhanced TNF-α secretion in RAW264.7 macrophages in a largely PKA-dependent fashion.
abstract: Autoantibodies against the second extracellular loop of β(1) -adrenergic receptor (β(1) -AA) not only contribute to increased susceptibility to heart failure, but also play a causative role in myocardial remodeling through their catecholamine-like effects via binding with the β(1) -adrenergic receptor. The current study was designed to determine whether β(1) -AA isolated from the sera of heart failure patients could cause TNF-α secretion from the murine macrophage-like cell line RAW264.7. Blood samples were collected from 40 patients who had suffered heart failure, as well as from 40 healthy subjects. The titer of β(1) -AA and the level of TNF-α were detected using ELISA. The effect of β(1) -AA on murine macrophage-like cell line RAW264.7 proliferation was detected by CCK-8 kits and CFSE assay. Western blot assay was used to analyze the expression of phospho-VASP. β(1) -AA appeared more frequently in patients with heart failure than in healthy subjects. The β(1) -AA isolated from heart failure patients promoted an increase of TNF-α levels, which could be completely blocked by the selective β(1) -adrenergic receptor antagonist metoprolol and the second extracellular loop of β(1) -adrenergic receptor (β(1) -AR-EC(II) ), but only partially inhibited by PKA inhibitor H89. Furthermore, the β(1) -AA could enhance the proliferation of RAW264.7 cells in vitro. Meanwhile, the expression of phospho-VASP was markedly increased in the presence of β(1) -AA. These results demonstrate for the first time that the β(1) -AA isolated from heart failure patients could bind with β(1) -AR on the surface of RAW264.7 cells, causing the release of TNF-α largely in a PKA-dependent fashion.
authors.affiliation: Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing 100069, P.R. China.
authors.forename: Yunhui
authors.initials: Y
authors.lastname: Du
authors.forename: Li
authors.initials: L
authors.lastname: Yan
authors.forename: Hongwei
authors.initials: H
authors.lastname: Du
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.forename: Fan
authors.initials: F
authors.lastname: Ding
authors.forename: Lin
authors.initials: L
authors.lastname: Quan
authors.forename: Xiuli
authors.initials: X
authors.lastname: Cheng
authors.forename: Kai
authors.initials: K
authors.lastname: Song
authors.forename: Huirong
authors.initials: H
authors.lastname: Liu
mesh_terms: D058671:Adrenergic beta-1 Receptor Antagonists / Q000378:metabolism; D000818:Animals; D000918:Antibody Specificity; D001323:Autoantibodies / Q000097:blood* / Q000276:immunology / Q000494:pharmacology; D015415:Biomarkers / Q000378:metabolism; D015153:Blotting, Western; D016022:Case-Control Studies; D015815:Cell Adhesion Molecules / Q000378:metabolism; D002460:Cell Line; D049109:Cell Proliferation; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D006333:Heart Failure / Q000276:immunology / Q000473:pathology*; D006801:Humans; D008264:Macrophages / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D008790:Metoprolol / Q000494:pharmacology; D051379:Mice; D008840:Microfilament Proteins / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D011933:Reagent Kits, Diagnostic; D018342:Receptors, Adrenergic, beta-1 / Q000276:immunology* / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000097:blood / Q000378:metabolism*; D000098662:Vasodilator-Stimulated Phosphoprotein
chemical_list: D058671:Adrenergic beta-1 Receptor Antagonists; D001323:Autoantibodies; D015415:Biomarkers; D015815:Cell Adhesion Molecules; D008840:Microfilament Proteins; D010750:Phosphoproteins; D011933:Reagent Kits, Diagnostic; D018342:Receptors, Adrenergic, beta-1; D014409:Tumor Necrosis Factor-alpha; D000098662:Vasodilator-Stimulated Phosphoprotein; D017868:Cyclic AMP-Dependent Protein Kinases; D008790:Metoprolol