Toll-like receptor 4 contributes to vascular remodelling and endothelial dysfunction in angiotensin II-induced hypertension

This is the peer-reviewed version of the following article: "Toll-like receptor 4 contributes to vascular remodelling and endothelial dysfunction in angiotensin II-induced hypertension", British Journal of Pharmacology 172.12 (2015): 3159-76 which has been published in final form at http://dx.doi.org/10.1111/bph.13117 This article may be used for non-commercial purposes in accordance with Wiley-VCH Terms and Conditions for Self-ArchivingBackground 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. Experimental Approach 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). Key Results 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 alterationsThis work was supported by Ministerio de Economía y Competitividad (SAF2012-36400), Instituto de Salud Carlos III (Red de Investigación Cardiovascular RD12/0042/0024 and RD12/0042/0033) and URJC (PRIN13_CS12). AMB was supported by the Ramón y Cajal Program (RYC-2010-06473)

The Melatonin Derivative ITH13001 Prevents Hypertension and Cardiovascular Alterations in Angiotensin II-Infused Mice

Inflammatory mechanisms and oxidative stress seem to contribute to the pathogenesis of hypertension. ITH13001 is a melatoninphenyl-acrylate hybrid that moderately induces the antioxidant transcription factor Nrf2 (nuclear factor erythroid 2–related factor 2) and has a potent oxidant scavenging effect compared with other derivatives of its family. Here we investigated the effect of ITH13001 on hypertension and the associated cardiovascular alterations. Angiotensin II (AngII)-infused mice were treated with ITH13001 (1 mg/kg per day, i.p.) for 2 weeks. The ITH13001 treatment prevented: 1) the development of hypertension, cardiac hypertrophy, and increased collagen and B-type natriuretic peptide (Bnp) expression in the heart; 2) the reduction of elasticity, incremental distensibility, fenestrae area, intraluminal diameter, and endothelial cell number in mesenteric resistance arteries (MRA); 3) the endothelial dysfunction in aorta and MRA; 4) the plasma and cardiovascular oxidative stress and the reduced aortic nitric oxide (NO) bioavailability; 5) the increased cardiac levels of the cytokines interleukin (IL)-1b, IL-6, and C-C motif chemokine ligand 2 (Ccl2), the T cell marker cluster of differentiation 3 (Cd3), the inflammasome NLRP3 (NOD-, LRR-, and pyrin domain-containing protein 3), the proinflammatory enzymes inducible nitric oxide synthase (iNOS) and COX-2, the toll-like receptor 4 (TLR4) adapter protein myeloid differentiation primary response 88 (MyD88), and the nuclear factor kappa B (NF-jB) subunit p65; 6) the greater aortic expression of the cytokines tumor necrosis factor alpha (Tnf-a), Ccl2 and IL-6, Cd3, iNOS, MyD88, and NLRP3. Although ITH13001 increased nuclear Nrf2 levels and heme oxygenase 1 (HO-1) expression in vascular smooth muscle cells, both cardiac and vascular Nrf2, Ho-1, and NADPH quinone dehydrogenase 1 (Nqo1) levels remained unmodified irrespective of AngII infusion. Summarizing, ITH13001 improved hypertension-associated cardiovascular alterations independently of Nrf2 pathway activation, likely due to its direct antioxidant and anti-inflammatory properties. Therefore, ITH13001 could be a useful therapeutic strategy in patients with resistant hypertension

Pioglitazone modulates the vascular contractility in hypertension by interference with ET-1 pathway

Endothelin-1 (ET-1) is an important modulator of the vascular tone and a proinflammatory molecule that contributes to the vascular damage observed in hypertension. Peroxisome-proliferator activated receptors-γ (PPARγ) agonists show cardioprotective properties by decreasing inflammatory molecules such as COX-2 and reactive oxygen species (ROS), among others. We investigated the possible modulatory effect of PPARγ activation on the vascular effects of ET-1 in hypertension. In spontaneously hypertensive rats (SHR), but not in normotensive rats, ET-1 enhanced phenylephrineinduced contraction through ETA by a mechanism dependent on activation of TP receptors by COX-2- derived prostacyclin and reduction in NO bioavailability due to enhanced ROS production. In SHR, the PPARγ agonist pioglitazone (2.5 mg/Kg·day, 28 days) reduced the increased ETA levels and increased those of ETB. After pioglitazone treatment of SHR, ET-1 through ETB decreased ROS levels that resulted in increased NO bioavailability and diminished phenylephrine contraction. In vascular smooth muscle cells from SHR, ET-1 increased ROS production through AP-1 and NFκB activation, leading to enhanced COX-2 expression. These effects were blocked by pioglitazone. In summary, in hypertension, pioglitazone shifts the vascular ETA/ETB ratio, reduces ROS/COX-2 activation and increases NO availability; these changes explain the effect of ET-1 decreasing phenylephrine-induced contractionThis work was supported by the Spanish Ministerio de Ciencia, Innovación y Universidades (SAF2015-69294-R and SAF2016-80305-P), Instituto de Salud Carlos III (CIBER de Enfermedades Cardiovasculares, CB16.11.00286), Comunidad de Madrid (B2017/BMD-3676) and Fondo Europeo de Desarrollo Regional (FEDER) a way to build Europ

Involvement of protein tyrosine phosphatases and inflammation in hypothalamic insulin resistance associated with ageing: Effect of caloric restriction

Aged Wistar rats present central insulin resistance associated with ageing. Several steps of the insulin signaling pathway have been described to be impaired in aged rats at hypothalamic level. In the present article we have explored possible alterations in protein tyrosine phosphatases (PTPs) involved in insulin receptor dephosphorylation, as well as pro-inflammatory pathways and serine kinases such as inhibitory kappa β kinase-nuclear factor kappa-B (IKKβ-NFκB), p38 mitogen-activated protein kinase (p38) and protein kinase C θ (PKCθ) that may also be involved in the decreased insulin signaling during ageing. We detected that ageing brings about a specific increase in insulin receptor tyrosine phosphatase activity and PTP1B serine phosphorylation. Increased association of PTP1B and leukocyte common antigen-related tyrosine protein phosphatase (LAR) with insulin receptor was also observed in hypothalamus from aged rats. Besides these mechanisms, increased activation of the IKKβ-NFκB pathway, p38 and PKCθ serine/threonine kinases were also detected. These data contribute to explain the hypothalamic insulin resistance associated with ageing. Caloric restriction ameliorates most of the effects of ageing on the above mentioned increases in PTPs and serine/threonine kinases activities and points to age-associated adiposity and inflammation as key factors in the development of age-associated insulin resistance. © 2012 Elsevier Ireland Ltd.Ministerio de Ciencia y Tecnología; Universidad Rey Juan Carlos; Comunidad de Madrid; Fundación Ramón ArecesPeer Reviewe