Immunoglobulin E (IgE) associates with allergic responses, but we found that its serum levels are enhanced in patients with acute myocardial infarction or unstable angina pectoris;they are nearly double those in patients with stable angina pectoris or without coronary heart disease. Both IgE and its high-affinity receptor Fc?R1 were expressed highly in human atherosclerotic lesions, localized to areas rich in macrophages (M?), and colocalized to lesion smooth-muscle cells (SMCs) and endothelial cells (ECs). Preliminary experiments showed that in the absence of Fc?R1 ?-subunit, atherosclerosis-prone apolipoprotein E-deficient (Apoe-/-) mice developed 75% fewer lipid depositions in the thoracic-abdominal aorta and had a >50% reduction in atherosclerotic lesion sizes in the aortic arch, compared with Apoe-/- control mice. In vitro cell culture studies demonstrated that IgE induced activation of M?, SMC, and EC mitogen-activated protein kinase (MAPK) pathway, along with enhanced inflammatory molecule production and apoptosis. Surprisingly, IgE stimulated a complex formation between Fc?R1 ?-chain and Toll-like receptor 4 (TLR4). Both Fc?R1 ?-subunit and TLR4 are necessary for IgE-induced M? cytokine and chemokine expression and apoptosis. Furthermore, these activities of IgE on M? associate with activation of Na+-H+ exchanger NHE1, followed by extracellular pH reduction. These novel preliminary findings are consistent with prior observations that in human atherosclerotic lesions, apoptotic cells cluster around lipid-rich necrotic cores, where the pH values are significantly lower (pH 7.15?0.01) than in other areas of the same lesions (pH 7.55?0.32, P=0.0001). Therefore, we hypothesize that IgE contributes to atherosclerosis by regulating M?, vascular SMC, and EC inflammation and apoptosis, and that these processes depend on Fc?R1 and TLR4 interaction as well as on NHE1 activation. We propose two specific aims to test this hypothesis: 1). To examine the molecular mechanisms by which IgE stimulates M? and vascular SMC and EC inflammation and apoptosis. 2). To examine whether inhibition or deficiency of IgE or IgE receptor Fc?R1 reduces atherosclerosis, and to test the importance of IgE-mediated M? activation in atherogenesis. We anticipate that the experiments proposed in both aims will establish an important and novel role of IgE in M? and vascular cell pathobiology, and a direct participation of IgE in atherogenesis.

Public Health Relevance

IgE is produced by plasma cells in response to allergic reactions. Recent discoveries of mast cell functions in atherosclerosis, and our preliminary studies of in vitro cell culture and in vivo mouse experimental atherosclerosis, prompted the hypothesis that IgE stimulates inflammatory cell and vascular cell inflammation and apoptosis, thereby promoting atherogenesis. These IgE activities are mediated by coordinate interactions between the IgE receptor Fc?R1 and TLR4, and via activation of the Na+-H+ exchanger NHE1. Deficiency or pharmacological inactivation of Fc?R1, TLR4, or NHE1 blocks IgE activities, and may thus reduce atherogenesis.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
2R01HL081090-05A1
Application #
8297031
Study Section
Atherosclerosis and Inflammation of the Cardiovascular System Study Section (AICS)
Program Officer
Ershow, Abby
Project Start
2005-07-01
Project End
2016-02-29
Budget Start
2012-04-01
Budget End
2013-02-28
Support Year
5
Fiscal Year
2012
Total Cost
$425,055
Indirect Cost
$175,055
Name
Brigham and Women's Hospital
Department
Type
DUNS #
030811269
City
Boston
State
MA
Country
United States
Zip Code
02115
Liu, Cong-Lin; Wang, Yi; Liao, Mengyang et al. (2016) Allergic lung inflammation promotes atherosclerosis in apolipoprotein E-deficient mice. Transl Res 171:1-16
Liu, Cong-Lin; Zhang, Jin-Ying; Shi, Guo-Ping (2016) Interaction between allergic asthma and atherosclerosis. Transl Res 174:5-22
Liu, Cong-Lin; Wemmelund, Holger; Wang, Yi et al. (2016) Asthma Associates With Human Abdominal Aortic Aneurysm and Rupture. Arterioscler Thromb Vasc Biol 36:570-8
Liu, Cong-Lin; Wang, Yi; Liao, Mengyang et al. (2016) Allergic Lung Inflammation Aggravates Angiotensin II-Induced Abdominal Aortic Aneurysms in Mice. Arterioscler Thromb Vasc Biol 36:69-77
Xu, Junyan; Lu, Xiaotong; Shi, Guo-Ping (2015) Vasa vasorum in atherosclerosis and clinical significance. Int J Mol Sci 16:11574-608
Wang, Jing; Sukhova, Galina K; Liu, Jian et al. (2015) Cathepsin G deficiency reduces periaortic calcium chloride injury-induced abdominal aortic aneurysms in mice. J Vasc Surg 62:1615-24
Zhou, Yi; Yu, Xueqing; Chen, Huimei et al. (2015) Leptin Deficiency Shifts Mast Cells toward Anti-Inflammatory Actions and Protects Mice from Obesity and Diabetes by Polarizing M2 Macrophages. Cell Metab 22:1045-58
Shi, Guo-Ping; Bot, Ilze; Kovanen, Petri T (2015) Mast cells in human and experimental cardiometabolic diseases. Nat Rev Cardiol 12:643-58
Lee, Yun-Jung; Liu, Conglin; Liao, Mengyang et al. (2015) Deficiency of FcϵR1 Increases Body Weight Gain but Improves Glucose Tolerance in Diet-Induced Obese Mice. Endocrinology 156:4047-58
Bot, Ilze; Shi, Guo-Ping; Kovanen, Petri T (2015) Mast cells as effectors in atherosclerosis. Arterioscler Thromb Vasc Biol 35:265-71

Showing the most recent 10 out of 69 publications