Toll-like receptor 4 contributes to vascular remodelling and endothelial dysfunction in angiotensin II-induced hypertension.
Br J Pharmacol
; 172(12): 3159-76, 2015 Jun.
Article
en En
| MEDLINE
| ID: mdl-25712370
ABSTRACT
BACKGROUND AND PURPOSE:
Toll-like receptor 4 (TLR4) signalling contributes to inflammatory cardiovascular diseases, but its role in hypertension and the associated vascular damage is not known. We investigated whether TLR4 activation contributed to angiotensin II (AngII)-induced hypertension and the associated vascular structural, mechanical and functional alterations. EXPERIMENTALAPPROACH:
AngII was infused (1.44 mg · kg(-1) · day(-1), s.c.) for 2 weeks in C57BL6 mice, treated with a neutralizing anti-TLR4 antibody or IgG (1 µg · day(-1); systolic BP (SBP) and aortic cytokine levels were measured. Structural, mechanical and contractile properties of aortic and mesenteric arterial segments were measured with myography and histology. RT-PCR and Western blotting were used to analyse these tissues and cultured vascular smooth muscle cells (VSMC) from hypertensive rats (SHR). KEYRESULTS:
Aortic TLR4 mRNA levels were raised by AngII infusion. Anti-TLR4 antibody treatment of AngII-treated mice normalised (i) increased SBP and TNF-α, IL-6 and CCL2 levels; (ii) vascular structural and mechanical changes; (iii) altered aortic phenylephrine- and ACh-induced responses; (iv) increased NOX-1 mRNA levels, superoxide anion production and NAD(P)H oxidase activity and effects of catalase, apocynin, ML-171 and Mito-TEMPO on vascular responses; and (v) reduced NO release and effects of L-NAME on phenylephrine-induced contraction. In VSMC, the MyD88 inhibitor ST-2825 reduced AngII-induced NAD(P)H oxidase activity. The TLR4 inhibitor CLI-095 reduced AngII-induced increased phospho-JNK1/2 and p65 NF-κB subunit nuclear protein expression. CONCLUSIONS AND IMPLICATIONS TLR4 up-regulation by AngII contributed to the inflammation, endothelial dysfunction, vascular remodelling and stiffness associated with hypertension by mechanisms involving oxidative stress. MyD88-dependent activation and JNK/NF-κB signalling pathways participated in these alterations.
Texto completo:
1
Base de datos:
MEDLINE
Asunto principal:
Angiotensina II
/
Receptor Toll-Like 4
/
Remodelación Vascular
/
Hipertensión
Idioma:
En
Revista:
Br J Pharmacol
Año:
2015
Tipo del documento:
Article