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Background Vascular complications are major causes of disability and death in people with diabetes mellitus (DM). Nitric oxide (NO) supplement may help prevent vascular complications and is an attractive treatment option for DM. Hydroxytyrosol (HT) is a major polyphenol in olive oil. It is mainly used as a dietary supplement because of its antioxidant effect. Purpose We aimed to determine the effects of hydroxytyrosol nitric oxide (HT-NO) on oxidative stress and NO level as well as related mechanisms. Study Design/Methods The effects of HT-NO on oxidative stress and NO level were examined by using diabetic mouse model and HUVECs. Results Our results showed that HT-NO has antioxidant and NO-releasing activities in vitro and in DM mice. HT-NO not only decreased blood glucose and oxidative stress but also increased NO level and deacetylase Sirtuin 1 (SIRT1) expression in DM mice and high glucose (HG)-stimulated HUVECs. Further studies found that SIRT1 activation augmented the effect of HT-NO on eNOS phosphorylation in HG-stimulated HUVECs. However, the promotive effect of HT-NO on eNOS phosphorylation was abolished by SIRT1 knockdown. Most importantly, HT-NO inhibited reactive oxygen species (ROS) production through SIRT1 in HUVECs. The ROS scavenger enhanced the effect of HT-NO on eNOS phosphorylation. Conclusion These results suggest that HT-NO regulates oxidative stress and NO production partly through SIRT1 in DM mice and HG-stimulated HUVECs.

Hydroxytyrosol (HT), a phenolic compound in olive oil, exerts an anti-inflammatory effect in cardiovascular diseases. Recent studies found that autophagy was a therapeutic target of diseases. However, the effect of HT on autophagy in vascular adventitial fibroblasts (VAFs) remains unknown. Thus, in this study, we aimed to determine the effect of HT on cell autophagy and related signaling pathway and whether HT regulates the inflammatory response through autophagy in VAFs. Our results showed that HT promoted cell autophagy by increasing the conversion of LC3 and Beclin1 expression and the autophagic flux in VAFs stimulated with tumor necrosis factor-α (TNF-α). HT also upregulated the expression of the deacetylase sirtuin 1 (SIRT1) protein and mRNA compared with the TNF-α group. The molecular docking studies showed the good compatibility between HT and SIRT1, indicating that HT might act through SIRT1. Further study found that HT regulated autophagy through SIRT1-mediated Akt/mTOR suppression in VAFs. In addition, HT inhibited TNF-α-induced inflammatory response in VAFs through SIRT1. Furthermore, the study showed that HT inhibited the inflammatory response of VAFs through autophagy. These findings indicate that HT regulates the autophagy of VAFs through SIRT1-mediated Akt/mTOR suppression and then inhibits the inflammatory response of VAFs.

Emerging evidence suggests that inflammation plays a pivotal role in Atherosclerosis. Sirtuin 6 (SIRT6), a member of NAD+-dependent protein lysine deacylases of the sirtuin family, plays an important role in the regulation of metabolism, aging and stress resistance. However, the role of SIRT6 in vascular inflammation and its molecular mechanism is unknown. The present study showed that TNF-α significantly reduced the expression of SIRT6 protein and mRNA in a concentration- and time-dependent manner and increased the expression of monocyte chemotactic protein 1 (MCP-1), interleukin (IL) -6 and IL-1β in human umbilical vein endothelial cells (HUVECs). Overexpression of SIRT6 but not its catalytically inactive mutant inhibited TNF-α-induced expression of MCP-1, IL-6 and IL-1β. Knockdown of SIRT6 significantly enhanced TNF-α-induced expression of MCP-1, IL-6 and IL-1β. Moreover, knockdown of SIRT6 reduced TNF-α-induced nuclear factor erythroid 2 related factor 2 (NRF2) nucleus protein expression, whereas knockdown of NRF2 significantly enhanced TNF-α-induced expression of MCP-1, IL-6 and IL-1β. In addition, overexpression of SIRT6 increased NRF2 and its target genes expression, and knockdown of SIRT6 decreased NRF2 and its target genes expression. Meanwhile, knockdown of SIRT6 inhibited NRF2 nucleus protein expression. Further, knockdown of SIRT6 decreased phosphorylation of NRF2, overexpression of SIRT6 increased phosphorylation of NRF2. SIRT6 interacted with NRF2. In vivo, the levels of TNF-α and IL-1β were increased in the serum of hyperlipidemia mice. Hyperlipidemia-induced production of MCP-1, IL-6 and IL-1β was significantly augmented in the endothelium specific SIRT6 knockout mice. In contrast, the expression of NRF2 and its target genes was reduced. Taken together, these results indicate that SIRT6 protects against vascular inflammation via its deacetylase activity and the NRF2-dependent signaling pathway.

Emerging evidences indicated that NLRP3 inflammasome initiates inflammatory response involved in cardiovascular disease. Nicotinic acid (NA) has been known to possess potential anti-inflammatory property. The aim of this study was to investigate the effect of NA on the activation of NLRP3 inflammasome and the underlying mechanisms. It was found that lipopolysaccharide (LPS) and adenosine triphosphate (ATP) triggered the activation of NLRP3 inflammasome in human umbilical vein endothelial cells (HUVECs). NA inhibited NLRP3 inflammasome activation and subsequent caspase-1 cleavage as well as interleukin (IL)-1β secretion. Moreover, NA administration up-regulated SIRT1 expression in HUVECs stimulated with LPS plus ATP. Importantly, knockdown of SIRT1 reversed the inhibitory effect of NA on the activation of NLRP3 inflammasome. Further study revealed that NA also decreased the generation of reactive oxygen species (ROS) in HUVECs. In addition, NA inhibited NLRP3 inflammasome activation partly through suppression of ROS. Taken together, these findings indicate that NA is able to regulate the activation of NLRP3 inflammasome in HUVECs, which may be partly mediated by SIRT1 and ROS.

Nicotinic acid (NA) has recently been shown to inhibit inflammatory response in cardiovascular disease. Sirtuin1 (SIRT1), a NAD(+)-dependent class III histone deacetylase, participates in the regulation of cellular inflammation. We hypothesized that dietary supplementation of NA could attenuate vascular inflammation via modulation of SIRT1 pathway. New Zealand White rabbits received chow or chow supplemented with 0.6% (wt/wt) NA for 2 weeks. Acute vascular inflammation was induced in the animals by placing a non-occlusive silastic collar around the left common carotid artery. At 24 h after collar implantation, the collar-induced production of C-reactive protein and monocyte chemotactic protein-1 was significantly suppressed in the NA-supplemented animals. Meanwhile, NA also decreased the expression of cluster of differentiation 40 (CD40) and CD40 ligand, but up-regulated SIRT1 expression, both in rabbits and in lipopolysaccharide-stimulated endothelial cells. Moreover, knockdown of SIRT1 reversed the inhibitory effect of NA on CD40 expression. Further study revealed that NA also decreased the expression of CD40 partly through mammalian target of rapamycin. These results indicate that NA protects against vascular inflammation via the SIRT1/CD40-dependent signaling pathway.

Imatinib (IM) represents a breakthrough in the treatment of chronic myeloid leukemia (CML) by inhibiting the activity of Bcr-Abl tyrosine kinase. However, many patients exhibit resistance to IM in the clinic. Recent studies have indicated that sirtuin 1 (SIRT1), a class III histone deacetylase (HDAC), plays an important role in leukemogenesis. In addition, some HDAC inhibitors are being tested to determine their anti-cancer activities in clinical trials. Divalproex sodium (DVPX), a first-line treatment for epilepsy, is also a HDAC inhibitor. However, it is unclear whether the anti-leukemic effects of IM in combination with DVPX on CML cells are related to SIRT1. The aim of this study was to investigate the effects of IM in combination with DVPX on cell viability, apoptosis, and cell cycle arrest in CML cells and to explore the underlying mechanisms. It was found that DVPX enhanced IM-induced cell growth inhibition, apoptosis and cell cycle arrest in K562-S and K562-G cells. Surprisingly, the level of p-Bcr-Abl was similar in K562-S and K562-G cells. Moreover, IM combined with DVPX had no effects on the phosphorylation of Bcr-Abl and its downstream target STAT5. Further study revealed that SIRT1 expression was higher in K562-G cells compared with K562-S cells. DVPX enhanced the inhibitory effect of IM on SIRT1 expression in K562-S and K562-G cells. Furthermore, knockdown of SIRT1 promoted apoptosis of K562-G cells treated with IM and DVPX. These results indicate that DVPX may increase the sensitivity of CML cells to IM and reverse IM resistance by regulating SIRT1 expression.

Oral candidiasis or thrush is a fungal infection due to Candida albicans, causing discomfort in areas inside mouth or tongue. The clinical application of antifungal reagent amphotericin B (AMB), which is believed to offer a better treatment for oral candidiasis, is greatly compromised by its toxicities (mainly nephrotoxicity) and poor solubility. In order to overcome these issues, we characterized AMB-loaded MPEG-PCL micelles in vitro and in vivo. In addition, the antifungal activities of AMB/MPEG-PCL micelles-loaded buccal tablet were also evaluated in vitro. We found that micelles system could significantly improve the solubility of AMB yet reduce the overall toxicity, while the buccal tablet system is capable to suppress C. albicans biofilm formation. Furthermore, the toxicity of the buccal tablet system is also reduced compared with other standard preparations. Therefore, the prepared tablet with AMB-loaded MPEG-PCL micelles as oral topical preparations has the potential to improve current treatment of superficial oral C. albicans infections.

Dihydromyricetin (DHM), a bioactive flavonoid component isolated from Ampelopsis grossedentata, is known to have anti-inflammatory effect, but the effect of DHM on acute lung injury (ALI) is largely unknown. Here, we investigated the effect of DHM on ALI and the underlying mechanism by bioinformatic analyses and animal experiments. We found that pretreatment with DHM ameliorated lung pathological changes and suppressed the inflammation response in lung tissues after LPS challenge. The potential targets of DHM were predicted by DDI-CPI and DRAR-CPI tools and analyzed using the STRING server to predict the functionally related signaling pathways, such as MAPK signaling. Molecular docking calculations indicated that DHM could be embedded tightly into the binding pocket of ERK, JNK, and p38. Furthermore, the activation of MAPK signaling induced by LPS was inhibited by DHM. In conclusion, these findings suggest that DHM may exert its protective effect on ALI by inhibiting MAPK signaling. The present study supports a potential clinical application for DHM in treating ALI and provides a novel design that combines in silico methods with in vivo experiments for drug research.

Sitagliptin has recently been shown to inhibit inflammatory response in cardiovascular disease. Sirtuin6 (SIRT6), a NAD+-dependent class III histone deacetylase, participates in the regulation of cellular inflammation. We hypothesized that sitagliptin could attenuate vascular inflammation via modulation of SIRT6 pathway. It was found that sitagliptin decreased the expression of monocyte chemotactic protein-1 (MCP-1), interleukin (IL)-6 and IL-1β, but up-regulated SIRT6 expression, both in mice and in TNF-α-stimulated endothelial cells. Moreover, knockdown of SIRT6 reversed the inhibitory effect of sitagliptin on MCP-1, IL-6 and IL-1β expression. Further study revealed that sitagliptin also decreased the expression of MCP-1, IL-6 and IL-1β partly through suppression of reactive oxygen species (ROS). In vivo, hypercholesterolemia in mice was induced by intraperitoneal administration of poloxamer 407 for 1 month. Hyperlipidemia-induced production of MCP-1, IL-6 and IL-1β was significantly suppressed in the sitagliptin-supplemented animals, but the effect of was abolished by SIRT6 knockout in endothelium. These results indicate that sitagliptin protects against vascular inflammation via the SIRT6/ROS-dependent signaling pathway.

Background: Recently, the effects of hydroxytyrosol on autophagy during acute lung injury (ALI) have drawn increasing attention. Objective: We explored the underlying molecular mechanisms by which hydroxytyrosol exerts its anti-inflammatory effects in a murine model of ALI by up-regulating autophagy. Methods: Male BALB/c mice, challenged with intranasal instillations of LPS, were treated with or without hydroxytyrosol (HT, 100 mg/kg, intragastrically) 1 h prior to LPS exposure. Twenty-four hours later, lung and bronchoalveolar lavage (BAL) fluid samples were obtained for the determination of lung wet to dry weight (W/D) ratios, protein leakage levels, and differential counts of inflammatory cells in BAL fluid. LPS-induced cytokine activity, inflammatory factor levels, sirtuin (SIRT1/3/6) expression, mitogenactivated protein kinase (MAPK) activation, and autophagy marker expression in ALImice were examined by western blotting and staining methods. Molecular docking between HT and SIRT and MAPK was studied with a Sybyl/Surflex module. Results: LPS-stimulated SIRT inhibition, MAPK phosphorylation, and autophagy suppression were all notably abolished by HT administration. HT treatment significantly attenuated pulmonary edema and inflammatory cell infiltration into lung tissues, accompanied by decreased lung W/D ratios, protein concentrations, and inflammatory cell levels in BAL fluid. LPS driven release of inflammatory mediators, including TNF-α, IL-1β, IL-6, IL-10, and MCP-1, was strongly regulated by HT. Conclusions: The protective effect of HT on lung inflammation in ALI mice may be attributed to the promotion of autophagy, which is likely associated with the activation of the SIRT/MAPK signaling pathway. Importantly, this study provides new insight into the molecular mechanisms of HT and its therapeutic potential in the treatment of acute respiratory distress syndrome.

Cordycepin (Cor), which is a naturally occurring nucleoside derivative isolated from Cordyceps militaris, has been shown to exert excellent antiinflammatory activity in a murine model of acute lung injury. Thus, this study aimed to evaluate the antiasthmatic activity of Cor (10, 20, and 40 mg/kg) and to investigate the possible underlying molecular mechanisms. We found that Cor attenuated airway hyperresponsiveness, mucus hypersecretion, and ovalbumin (Ova)-specific immunoglobulin (Ig) E, and alleviated lung inflammation with decreased eosinophils and macrophages in the bronchoalveolar lavage (BAL) fluid. Notably, Cor reduced the upregulation of eotaxin, intercellular cell adhesion molecule-1 (ICAM-1), IL-4, IL-5, and IL-13 in the BAL fluid. Furthermore, Cor markedly blocked p38-MAPK and nuclear factor-kappaB (NF-κB) signalling pathway activation in the Ova-driven asthmatic mice. In conclusion, this study demonstrated that some of the antiasthmatic benefits of Cor attributable to diets and/or tonics may result from reductions in inflammatory processes and that these antiasthmatic properties involve the inhibition of Th2-type responses through the suppression of the p38-MAPK and NF-κB signalling pathways.

Hydroxysafflor yellow A (HSYA), the main active natural constituent extracted from Carthamus tinctorius L., has been widely used for the treatment of cerebrovascular and cardiovascular diseases. The aim of this study is to explore the effect of HSYA on alcohol-induced liver injury and the underlying mechanism. Male Sprague-Dawley rats were used to establish the liver injury model induced by alcohol. HSYA treatment ameliorated serum biochemical indicators by reducing the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), hyaluronan (HA), laminin (LN), and type III precollagen (III-C) in rats. HSYA efficiently increased the activity and messenger RNA (mRNA) of superoxide dismutase (SOD) and glutathione peroxidase (GPx) in rat liver tissue compared with those of model group, which was obviously reduced by alcohol. HSYA also apparently decreased the levels of reactive oxygen species (ROS) and malondialdehyde (MDA) in rat liver tissue compared with those of model group, which was obviously enhanced by alcohol. Histological studies demonstrated that HSYA substantially reduced the number of macro- and micro-vesicular steatosis, suppressed hepatic fibrogenesis and shrunk ballooning degeneration areas, ameliorated the severity of liver damage induced by long-term drinking, and finally improved the liver architecture. In addition, immunohistochemistry study indicated that the activation of transforming growth factor β1 (TGF-β1) stimulated by alcohol in rat liver tissue was significantly blocked by HSYA. Collectively, these data demonstrated that HSYA can effectively protect the liver of rats from long-term alcohol injury, which relates with the enhanced antioxidant capacity of liver tissues and inhibition of TGF-β1 expression.

Intracellular reactive oxygen species (ROS) are derived from nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. Angiotensin II (Ang II) can cause endothelial dysfunction by promoting intracellular ROS generation. Safflor yellow B (SYB) effectively inhibits ROS generation by upregulating Bcl-2 expression. In this study, we examined the effects of SYB on Ang II-induced injury to human umbilical vein endothelial cells (HUVECs), and elucidated the roles of NADPH oxidase and Bcl-2. We treated cultured HUVECs with Ang II, SYB, and Bcl-2 siRNA, and determined NADPH oxidase activity and ROS levels. Furthermore, cellular and mitochondrial physiological states were evaluated, and the expression levels of target proteins were analyzed. Ang II significantly enhanced intracellular ROS levels, caused mitochondrial membrane dysfunction, and decreased cell viability, leading to apoptosis. This was associated with increased expression of AT1R and p22(phox), increased NADPH oxidase activity, and an increased ratio of Bax/Bcl-2, leading to decreases in antioxidant enzyme activities, which were further strengthened after blocking Bcl-2. Compared to Ang II treatment alone, co-treatment with SYB significantly reversed HUVEC injury. Taken together, these results demonstrate that SYB could significantly protect endothelial cells from Ang II-induced cell damage, and that it does so by upregulating Bcl-2 expression and inhibiting ROS generation.