Antioxidant protein peroxiredoxin 6 suppresses the vascular inflammation, oxidative stress and endothelial dysfunction in angiotensin II-induced endotheliocyte.

Cardiovascular disease (CVD) states are associated with endothelial dysfunction (ED) and increased production of ROS in endothelial cells. The present study aimed to explore the protective effects of antioxidant protein peroxiredoxin 6 (PRDX6) on angiotensin II (AngII)­induced human umbilical vein endothelial cell (HUVEC) dysfunction. To investigate cell viability, levels of inflammatory molecules and proteins were assayed using the CCK-8 assay and evaluated by ELISA and Western blot. NO and ROS levels were determined by Griess assay and the fluorescent probe DCFH-DA. Cell migration capacity was assessed by Transwell assay. AngII decreased cell viability and PRDX6, upregulated the expression levels of TNF-α, IL-6, IL-1ß, LDH and MDA, stimulated ROS production, and reduced NO synthase, the expressions of eNOS, MnSOD, ICAM-1, VCAM-1, and activated the MAPK family of signaling proteins. However, the stimulatory effects of AngII on HUVECs were remarkably suppressed by PRDX6. Furthermore, mercaptosuccinate (MS; PRDX6 inhibitor) had similar effects as AngII in aggravating HUVECs damage. Conversely, these adverse events caused by AngII and MS were obviously reversed by ML3404 and SP600125. The present study indicated that PRDX6 overexpression inactivated p38 MAPK and JNK pathway through decrease AngII-induced inflammation, oxidative stress and endothelial dysfunction leading to attenuation of endothelial cell damage.

Role of toll-like receptor 4 on lupus lung injury and atherosclerosis in LPS-challenge ApoE⁻/⁻ mice.

To investigate the pathologic mechanisms of toll-like receptor 4 (TLR4) in lung injury and atherosclerosis, ApoE⁻/⁻ or wild-type mice were intraperitoneally administered saline, lipopolysaccharides (LPS), or LPS plus TAK-242 (TLR4 inhibitor), respectively, twice a week for 4 weeks. Serum autoantibody of antinuclear antibody (ANA), anti-double-stranded DNA (anti-dsDNA), and cytokines of interferon-gamma (IFN-γ), tumor necrosis factor (TNF-α ), and interleukin-1 (IL-1ß) were assessed by ELISA. Hematoxylin and eosin (HE) and Perl's stains for lung pathomorphology as well as HE staining for atherosclerosis were employed. TLR4 in macrophages was detected by double immunofluorescent staining. While protein expressions of TLR4, nuclear factor-kappa B p65 (NF-κB p65), and B cell activating factor belonging to the TNF family (BAFF) were examined by immunohistochemistry. We found that serum autoantibody (ANA and anti-dsDNA), cytokines (IFN-γ, TNF-α, IL-1ß), lung inflammation, and intima-media thickness in brachiocephalic artery were obviously increased after LPS challenge in both genotypes, but to a lesser extent in wild-type strains. And those alterations were alleviated by coadministration of LPS and TAK-242. Mechanistically, upregulation of TLR4, NF-κb, and BAFF was involved. We concluded that TLR4/NF-κb/BAFF in macrophages might be a possible common autoimmune pathway that caused lung injury and atherosclerosis. TLR4 signal will be a therapeutic target in atherosclerosis and immune-mediated lung injury.