Activation of Toll-like receptor 3 increases mouse aortic vascular smooth muscle cell contractility through ERK1/2 pathway.
Activation of Toll-like receptor 3 (TLR3), a pattern recognition receptor of the innate immune system, is associated with vascular complications. However, whether activation of TLR3 alters vascular contractility is unknown. We, therefore, hypothesized that TLR3 activation augments vascular contractility and activates vascular smooth muscle cell (VSMC) contractile apparatus proteins. Male mice were treated with polyinosinic-polycytidylic acid (Poly I:C group, 14 days), a TLR3 agonist; control mice received saline (vehicle, 14 days). At the end of protocol, blood pressure was measured by tail cuff method. Aortas were isolated and assessed for contractility experiments using a wire myograph. Aortic protein content was used to determine phosphorylated/total interferon regulatory factor 3 (IRF3), a downstream target of TLR3 signaling, and ERK1/2 using Western blot. We investigated the TLR3/IRF3/ERK1/2 signaling pathway and contractile-related proteins such as phosphorylated/total myosin light chain (MLC) and caldesmon (CaD) in aortic VSMC primary cultures. Poly I:C-treated mice exhibited (vs. vehicle-treated mice) (1) elevated systolic blood pressure. Moreover, Poly I:C treatment (2) enhanced aortic phenylephrine-induced maximum contraction, which was suppressed by PD98059 (ERK1/2 inhibitor), and (3) increased aortic levels of phosphorylated IRF3 and ERK1/2. Stimulation of mouse aortic VSMCs with Poly I:C resulted in increased phosphorylation of IRF3, ERK1/2, MLC, and CaD. Inhibition of ERK1/2 abolished Poly I:C-mediated phosphorylation of MLC and CaD. Our data provide functional evidence for the role of TLR3 in vascular contractile events, suggesting TLR3 as a potential new therapeutic target in vascular dysfunction and regulation of blood pressure.
Department of Physiology, Georgia Regents University, Augusta, GA, USA.
Trevor
T
Hardigan
Department of Internal Medicine, University of Iowa, Iowa City, IA, USA.
Kathryn
K
Spitler
Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshy University, Shinagawa-ku, Tokyo, Japan.
Takayuki
T
Matsumoto
Department of Physiology, Georgia Regents University, Augusta, GA, USA. mcarrill@nyit.edu.|Department of Biomedical Sciences, New York Institute of Technology-College of Medicine, Northern Blvd, Old Westbury, NY, 11568, USA. mcarrill@nyit.edu.
Maria Alicia
MA
Carrillo-Sepulveda
D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000378:metabolism; D001794:Blood Pressure / Q000187:drug effects; D002148:Calmodulin-Binding Proteins / Q000378:metabolism; D050838:Interferon Regulatory Factor-3 / Q000235:genetics / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects* / Q000235:genetics*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009119:Muscle Contraction / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000502:physiology*; D018994:Myosin Light Chains / Q000378:metabolism; D011070:Poly I-C / Q000494:pharmacology; D051196:Toll-Like Receptor 3 / Q000819:agonists* / Q000378:metabolism
D002148:Calmodulin-Binding Proteins; D050838:Interferon Regulatory Factor-3; C494233:Irf3 protein, mouse; D018994:Myosin Light Chains; C519703:TLR3 protein, mouse; D051196:Toll-Like Receptor 3; D011070:Poly I-C
Aorta; ERK1/2; Toll-like receptor 3; Vascular smooth muscle; Vasoconstriction