Pioglitazone reduces angiotensin II-induced COX-2 expression through inhibition of ROS production and ET-1 transcription in vascular cells from spontaneously hypertensive rats

Abstract

Glitazones have anti-inflammatory properties by interfering with the transcription of proinflammatory genes, such as cyclooxygenase (COX)-2, and with ROS production, which are increased in hypertension. This study analyzed whether pioglitazone modulates COX-2 expression in hypertension by interfering with ROS and endothelin (ET)-1. In vivo, pioglitazone (2.5 mg·kg(-1)·day(-1), 28 days) reduced the greater levels of COX-2, pre-pro-ET-1, and NADPH oxidase (NOX) expression and activity as well as O2 (·-) production found in aortas from spontaneously hypertensive rats (SHRs). ANG II increased COX-2 and pre-pro-ET-1 levels more in cultured vascular smooth muscle cells from hypertensive rats compared with normotensive rats. The ETA receptor antagonist BQ-123 reduced ANG II-induced COX-2 expression in SHR cells. ANG II also increased NOX-1 expression, NOX activity, and superoxide production in SHR cells; the selective NOX-1 inhibitor ML-171 and catalase reduced ANG II-induced COX-2 and ET-1 transcription. ANG II also increased c-Jun transcription and phospho-JNK1/2, phospho-c-Jun, and p65 NF-κB subunit nuclear protein expression. SP-600125 and lactacystin, JNK and NF-κB inhibitors, respectively, reduced ANG II-induced ET-1, COX-2, and NOX-1 levels and NOX activity. Pioglitazone reduced the effects of ANG II on NOX activity, NOX-1, pre-pro-ET-1, COX-2, and c-Jun mRNA levels, JNK activation, and nuclear phospho-c-Jun and p65 expression. In conclusion, ROS production and ET-1 are involved in ANG II-induced COX-2 expression in SHRs, explaining the greater COX-2 expression observed in this strain. Furthermore, pioglitazone inhibits ANG II-induced COX-2 expression likely by interfering with NF-κB and activator protein-1 proinflammatory pathways and downregulating ROS production and ET-1 transcription, thus contributing to the anti-inflammatory properties of glitazones.

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

“…Here, we observed the NAD(P)H oxidase activity in VSMC induced by exposure to AngII for 1h was reduced by the MyD88 inhibitor ST‐2825 (Figure A). We have also reported that AngII increases oxidative stress in VSMC through JNK1/2 MAPK and NF‐κB (Pérez‐Girón et al ., ). The phosphorylation of JNK1/2, induced by exposure to AngII for 10 min, was reduced by the TLR4 inhibitor CLI‐095 (Figure B).…”

“…Another signalling pathway recruited by TLR4 activation, via the MyD88‐dependent pathway, is the MAPK cascade (Kawai and Akira, ). Previously, we have shown that JNK and NF‐κB contributed to the oxidative stress induced by AngII (Pérez‐Girón et al ., ). Here we showed, in VSMC, that AngII‐induced NAD(P)H oxidase activity was reduced by a specific MyD88 inhibitor.…”

“…Immunofluorescence was also used to detect p65 NF-κB subunit nuclear protein expression in cultured VSMC stimulated with AngII (100 nM, 45 min) after treatment or not with CLI-095 (1 μM, 1h), as described (Pérez-Girón et al, 2014). Cells were incubated overnight at 4°C with a rabbit polyclonal primary antibody against p65 (1:250, Santa Cruz Biotechnology).…”

Pioglitazone, a PPARγ agonist, attenuates PDGF-induced vascular smooth muscle cell proliferation through AMPK-dependent and AMPK-independent inhibition of mTOR/p70S6K and ERK signaling

“…It is noteworthy that the basal ERK phosphorylation in vascular cells is mediated in part by reactive oxygen species (ROS), including superoxide (O 2 − ) [57, 58]. In addition, PIO has been shown to inhibit NADPH oxidase-mediated generation of ROS in aortic tissues and VSMCs [59, 60]. Thus, it is likely that PIO inhibits the basal ERK activation by suppressing ROS production in VSMCs.…”

Hu antigen R is required for NOX-1 but not NOX-4 regulation by inflammatory stimuli in vascular smooth muscle cells

“…NOX-1 is an inducible gene and its expression is increased in vascular cells by several pro-inflammatory stimuli including AngII, interferon-γ (IFN-γ) and platelet derived growth factor (PDGF) [8–11]. Various transcription factors such as ATF-1 [12,13] or STAT [9] have binding sites in NOX-1 promoter and play an important role in its inducible expression.…”