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Endothelial nitric oxide synthase (eNOS) decreases following inflammatory stimulation. As a master regulator of endothelial homeostasis, maintaining optimal eNOS levels is important during cardiovascular events. However, little is known regarding the mechanism of eNOS protection. In this study, we demonstrate a regulatory role for endothelial expression of 2′–5′ oligoadenylate synthetase-like 1 (OASL1) in maintaining eNOS mRNA stability during athero-prone conditions and consider its clinical implications. A lack of endothelial Oasl1 accelerated plaque progression, which was preceded by endothelial dysfunction, elevated vascular inflammation, and decreased NO bioavailability following impaired eNOS expression. Mechanistically, knockdown of PI3K/Akt signaling-dependent OASL expression increased Erk1/2 and NF-κB activation and decreased NOS3 (gene name for eNOS) mRNA expression through upregulation of the negative regulatory, miR-584, whereas a miR-584 inhibitor rescued the effects of OASL knockdown. These results suggest that OASL1/OASL regulates endothelial biology by protecting NOS3 mRNA and targeting miR-584 represents a rational therapeutic strategy for eNOS maintenance in vascular disease. Maintaining optimal eNOS levels is important during cardiovascular events, although little is known regarding the mechanism of eNOS protection. Here, the authors show a regulatory role of endothelial OASL1 in maintaining eNOS mRNA stability and vascular biology under atheroprone conditions. [ABSTRACT FROM AUTHOR]

Activated macrophages show increased expression of vimentin, an intermediate filament protein. Macrophages secrete vimentin into extracellular space; however, the functions of extracellular vimentin and the process of vimentin secretion are not clearly defined. We found that oxidized low-density lipoproteins (oxLDL) via CD36 induced vimentin secretion in macrophages. We also revealed that extracellular vimentin induced macrophages to release inflammatory cytokines and augmented oxLDL-induced release of TNF-α and IL-6. Extracellular vimentin activated NF-κB signaling via phosphorylation of focal adhesion kinase (p-FAK) and IκB kinase (p-IκK). Extracellular vimentin also amplified the oxLDL-induced p-IκK increase and IκB decrease. Vimentin-induced TNF-α release was not dependent on Dectin-1, which is known to bind vimentin. We measured serum vimentin concentrations and found that patients with atherosclerotic coronary artery disease had higher levels of serum vimentin than normal subjects. Circulating oxLDL and vimentin concentrations showed a high degree of correlation. In mouse experiments, vimentin concentration was higher in the sera of apoE null mice with western diet–induced atherosclerosis than in the sera of chow diet–fed apoE null mice without atherosclerosis. We concluded that vimentin is secreted by oxLDL/CD36 interaction in macrophages and extracellular vimentin promotes macrophage release of pro-inflammatory cytokines. This may contribute to atherosclerotic inflammation and based on our analysis of serum vimentin, we suggest serum vimentin as a predictive marker for atherosclerosis. Key messages: OxLDL via CD36 induces secretion of vimentin, a cytoskeletal protein in macrophages. Extracellular vimentin induces macrophages to release proinflammatory cytokines such as tumor necrotizing factor-alpha (TNF-α) and this process is mediated by activation of focal adhesion kinase (FAK) and NF-ƙB signaling. Serum concentrations of vimentin in coronary artery disease patients are higher than that in control group. Vimentin concentration is strongly correlated with oxLDL concentration in serum. [ABSTRACT FROM AUTHOR]

Despite the introduction of statins for lowering LDL-C level, atherosclerotic cardiovascular disease (ASCVD) remains a leading cause of death and morbidity worldwide. Combination therapies with statin and other lipid-lowering drugs, including ezetimibe and proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, have unlocked additive benefits for treatment of ASCVD, but morbidity and mortality due to ASCVD remain high. New anti-inflammatory therapies have emerged for treatment and prevention of ASCVD to address these problems. Canakinumab neutralization of interleukin-1β (IL-1β) is the only verified therapy, and low-dose methotrexate holds promise due to its efficacy and safety for treatment of ASCVD. However, many agonistic and antagonistic candidates within inflammation pathways have failed to develop into useful drugs for ASCVD because of the complexity of the inflammatory process in atherosclerosis. In this review, we outline current and future pharmaceutical therapies for ASCVD in terms of lipid-modifying strategies and anti-inflammation treatments. [ABSTRACT FROM AUTHOR]

The production of type I interferon is essential for viral clearance but is kept under tight control to avoid unnecessary tissue damage from hyperinflammatory responses. Here we found that OASL1 inhibited translation of IRF7, the master transcription factor for type I interferon, and thus negatively regulated the robust production of type I interferon during viral infection. OASL1 inhibited the translation of IRF7 mRNA by binding to the 5′ untranslated region (UTR) of IRF7 and possibly by inhibiting scanning of the 43S preinitiation complex along the message. Oasl1−/− mice were resistant to viral infection because of the greater abundance of type I interferon, which suggests that OASL1 could be a potential therapeutic target for boosting the production of type I interferon during viral infection. [ABSTRACT FROM AUTHOR]

Sqstm1/p62 functions in the non-canonical activation of nuclear factor (erythroid-derived 2)-like 2 (Nrf2). However, its physiological relevance is not certain. Here, we show that p62−/− mice exhibited an accelerated presentation of ageing phenotypes, and tissues from these mice created a pro-oxidative environment owing to compromised mitochondrial electron transport. Accordingly, mitochondrial function rapidly declined with age in p62−/− mice. In addition, p62 enhanced basal Nrf2 activity, conferring a higher steady-state expression of NAD(P)H dehydrogenase, quinone 1 (Nqo1) to maintain mitochondrial membrane potential and, thereby, restrict excess oxidant generation. Together, the p62-Nrf2-Nqo1 cascade functions to assure mammalian longevity by stabilizing mitochondrial integrity. [ABSTRACT FROM AUTHOR]