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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Toll-like receptor 4 inhibition reduces vascular inflammation in spontaneously hypertensive rats

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Author(s):
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Bomfim, G. F. [1, 2] ; Echem, C. [1] ; Martins, C. B. [1] ; Costa, T. J. [1] ; Sartoretto, S. M. [1] ; Dos Santos, R. A. [1] ; Oliveira, M. A. [1] ; Akamine, E. H. [1] ; Fortes, Z. B. [1] ; Tostes, R. C. [3] ; Webb, R. C. [4] ; Carvalho, M. H. C. [1]
Total Authors: 12
Affiliation:
[1] Univ Sao Paulo, Inst Biomed Sci, Dept Pharmacol, BR-05508900 Sao Paulo - Brazil
[2] Univ Fed Mato Grosso, Inst Hlth Sci, Setor Ind, BR-78550000 Sinop, MT - Brazil
[3] Univ Sao Paulo, Ribeirao Preto Med Sch, Dept Pharmacol, BR-14049900 Sao Paulo - Brazil
[4] Georgia Regents Univ, Dept Physiol, Augusta, GA 30912 - USA
Total Affiliations: 4
Document type: Journal article
Source: Life Sciences; v. 122, p. 1-7, FEB 1 2015.
Web of Science Citations: 32
Abstract

Aims: Hypertension is associated with increased levels of circulating cytokines and recent studies have shown that innate immunity contributes to hypertension. The mechanisms which hypertension stimulates immune response remain unclear, but may involve formation of neo-antigens that activate the immune system. Toll like receptor 4 (TLR4) is an innate immune receptor that binds a wide spectrum of exogenous (lipopolysaccharide) and endogenous ligands. TLR4 signaling leads to activation of nuclear factor kappa B (NF kappa B) and transcription of genes involved in inflammatory response. We previously demonstrated that TLR4 blockade reduces blood pressure and the augmented vascular contractility in spontaneously hypertensive rats (SHR). Here we hypothesized that inhibition of TLR4 ameliorates the vascular inflammatory process by a NF kappa B signaling pathway. Main methods: SHR and Wistar rats were treated with anti-TLR4 antibody (1 mu g/day) or unspecific IgG for 15 days (i.P.). Key findings: Anti-TLR4 treatment decreased production of reactive oxygen species and expression of IL-6 cytokine in mesenteric resistance arteries from SHR, when compared with IgG-treated SHR. Anti-TLR4 treatment also abolished the increased vascular reactivity to noradrenaline observed in IgG-treated SHR, as described before, and inhibition of NF kappa B decreased noradrenaline responses only in IgG-treated SHR. Mesenteric arteries from SHR treated with anti-TLR4 displayed decreased expression of MyD88, but not TRIF, key molecules in TLR4 signaling. Phosphorylation of p38 and NF-kappa B p65 were decreased in arteries from anti-TLR4-treated SHR versus IgG-treated SHR. Significance: Together, these results suggest that TLR4 is a key player in hypertension and vascular inflammatory process by a NF kappa B signaling pathway. (C) 2014 Elsevier Inc. All rights reserved. (AU)