Inflammation In Vascular Endothelial Cells Research Articles

Quercetin ameliorates atherosclerosis by inhibiting inflammation of vascular endothelial cells via Piezo1 channels

BackgroundNatural antioxidants, exemplified by quercetin (Qu), have been shown to exert a protective effect against atherosclerosis (AS). However, the precise pharmacological mechanisms of Qu also remain elusive. PurposeHere, we aimed to uncover the anti-atherosclerotic mechanisms of Qu. Methods/Study designsThe inflammatory cytokine expression, activity of NLRP3 inflammasome and NF-κB, as well as mechanically activated currents and intracellular calcium levels were measured in endothelial cells (ECs). In addition, to explore whether Qu inhibited atherosclerotic plaque formation via Piezo1 channels, Ldlr−/- and Piezo1 endothelial-specific knockout mice (Piezo1△EC) were established. ResultsOur findings revealed that Qu significantly inhibited Yoda1-evoked calcium response in human umbilical vein endothelial cells (HUVECs), underscoring its role as a selective modulator of Piezo1 channels. Additionally, Qu effectively reduced mechanically activated currents in HUVECs. Moreover, Qu exhibited a substantial inhibitory effect on inflammatory cytokine expression and reduced the activity of NF-κB/NLRP3 in ECs exposed to ox-LDL or mechanical stretch, and these effects remained unaffected after Piezo1 genetic depletion. Furthermore, our study demonstrated that Qu substantially reduced the formation of atherosclerotic plaques, and this effect remained consistent even after Piezo1 genetic depletion. ConclusionThese results collectively provide compelling evidence that Qu ameliorates atherosclerosis by inhibiting the inflammatory response in ECs by targeting Piezo1 channels. In addition, Qu modulated atherosclerosis via inhibiting Piezo1 mediated NFκB/IL-1β and NLRP3/caspase1/ IL-1β axis to suppress the inflammation. Overall, this study reveals the potential mechanisms by which natural antioxidants, such as Qu, protect against atherosclerosis.

IGF-1 inhibits inflammation and accelerates angiogenesis via Ras/PI3K/IKK/NF-κB signaling pathways to promote wound healing

Exogenous insulin-like growth factor-1 (IGF-1) has been reported to promote wound healing through regulation of vascular endothelial cells (VECs). Despite the existing studies of IGF-1 on VEC and its role in angiogenesis, the mechanisms regarding anti-inflammatory and angiogenetic effects of IGF-1 remain unclear. In this study, we investigated the wound-healing process and the related signaling pathway of IGF-1 using an inflammation model induced by IFN-γ. The results demonstrated that IGF-1 can increase cell proliferation, suppress inflammation in VECs, and promote angiogenesis. In vivo studies further confirmed that IGF-1 can reduce inflammation, enhance vascular regeneration, and improve re-epithelialization and collagen deposition in acute wounds. Importantly, the Ras/PI3K/IKK/NF-κB signaling pathways was identified as the mechanisms through which IGF-1 exerts its anti-inflammatory and pro-angiogenic effects. These findings contribute to the understanding of IGF-1′s role in wound healing and may have implications for the development of new wound treatment approaches.

Retraction: Platelet-derived exosomal microRNA-25-3p inhibits coronary vascular endothelial cell inflammation through Adam10 via the NF-κB signaling pathway in ApoE-/- mice.

[This retracts the article DOI: 10.3389/fimmu.2019.02205.].

Nrf2-mediated redox balance alleviates LPS-induced vascular endothelial cell inflammation by inhibiting endothelial cell ferroptosis

Ferroptosis plays an important role in inflammation and oxidative stress. Whether ferroptosis is involved in the inflammation of vascular endothelial cells and its regulation mechanism remains unclear. We estimated the correlation between serum iron ion levels and the inflammation index of 33 patients with arteriosclerosis. In vitro, HUVECs with or without ferrostatin-1 were exposed to Lipopolysaccharide. Corresponding cell models to verify the target signaling pathway. The results showed that serum iron ion levels had a significant positive correlation with N ratio, N/L, LDL level, and LDL/HDL (P < 0.05), and a negative correlation with L ratio (P < 0.05) in the arteriosclerosis patients. In vitro, ferroptosis is involved in HUVECs inflammation. Ferrostatin-1 can rescue LPS-induced HUVECs inflammation by decreasing HMGB1/IL-6/TNF-α expression. Nrf2 high expression could protect HUVECs against ferroptosis by activating the GPX4/GSH system, inhibiting ferritinophagy, and alleviating inflammation in HUVECs by inhibiting HMGB1/IL-6/TNF-α expression. It also found that Nrf2 is a key adaptive regulatory factor in the oxidative damage of HUVECs induced by NOX4 activation. These findings indicated that ferroptosis contributed to the pathogenesis of vascular endothelial cell damage by mediating endothelial cell inflammation. Nrf2-mediated redox balance in vascular inflammation may be a therapeutic strategy in vascular diseases.

SMPDL3B is palmitoylated and stabilized by ZDHHC5, and its silencing aggravates diabetic retinopathy of db/db mice: Activation of NLRP3/NF-κB pathway

Abnormal inflammation of vascular endothelial cells occurs frequently in diabetic retinopathy (DR). Sphingomyelin phosphodiesterase acid-like 3B (SMPDL3B) is a lipid raft enzyme and plays an anti-inflammatory role in various diseases but its function in DR-related vascular endothelial dysfunction remains unknown. We first found that SMPDL3B expression was upregulated from week 10 to 18 in the retinal tissues of db/db mice. Particularly, the high expression of SMPDL3B was mainly observed in retinal vascular endothelium of DR mice. To interfere retinal SMPDL3B expression, adeno-associated viruses 2 (AAV-2) containing SMPDL3B specific shRNA (1233–1253 bp) were injected into the vitreous cavity of db/db mice. SMPDL3B silencing exacerbated the spontaneous DR by further activating the NF-κB/NLRP3 pro-inflammatory pathway. In vitro, human retinal microvascular endothelial cells (HRVECs) were infected with SMPDL3B-shRNA lentiviruses and then stimulated with 30 mM glucose (HG) for 24 h. SMPDL3B-silenced HRVECs secreted more interleukin-1β and had enhanced nuclear p65 translocation. Notably, HG treatment induced the palmitoylation of SMPDL3B. Zinc finger DHHC-type palmitoyltransferase 5 (ZDHHC5) is a palmitoyltransferase that catalyzes the palmitoylation of its substrates, HG exposure increased the interaction between ZDHHC5 and SMPDL3B in HRVECs. 2-BP, a palmitoylation inhibitor, accelerated the protein degradation of SMPDL3B, whereas palmostatin B, a depalmitoylation inhibitor, decreased its turnover rate in HRVECs. Collectively, the present study suggests a compensatory increase of SMPDL3B in HG-treated HRVECs and the retinal tissues of DR mice, indicating that SMPDL3B may be a potential target for DR treatment.

Ferulic acid suppresses the inflammation and apoptosis in Kawasaki disease through activating the AMPK/mTOR/NF-κB pathway.

Kawasaki disease (KD) is a self-limiting and acute systemic vasculitis of unknown etiology, mainly affecting children. Ferulic acid (FA), a natural phenolic substance, has multiple pharmacological properties, including anti-inflammatory, anti-apoptosis, and anti-fibrosis, and so on. So far, the protective effects of FA on KD have not been explored. In this study, we established Candida albicans water soluble fraction (CAWS)-induced mouse coronary artery vasculitis of KD model and the tumor necrosis factor α (TNF-α)-induced human umbilical vein endothelial cells (HUVECs) injury model to investigate the anti-inflammatory and anti-apoptosis effects of FA on KD, and try to elucidate the underlying mechanism. Our in vivo results demonstrated that FA exerted anti-inflammatory effects on KD by inhibiting the infiltration of CD45-positive leukocytes and fibrosis around the coronary artery. Additionally, FA downregulated the levels of inflammatory and chemotactic cytokines, alleviated splenomegaly, and exhibited anti-apoptotic effects on KD by reducing TUNEL-positive cells, downregulating BAX expression, and upregulating BCL-2 expression. In addition, Our in vitro findings showed that FA could effectively inhibit TNF-α-induced HUVEC inflammation like NF-κB inhibitor QNZ by downregulating the expression of pro-inflammatory cytokines as well as attenuated TNF-α-induced HUVEC apoptosis by reducing apoptotic cell numbers and the BAX/BCL-2 ratio, which could be reversed by the AMPK inhibitor compound c (CC). The further mechanistic study demonstrated that FA could restrain vascular endothelial cell inflammation and apoptosis in KD through activating the AMPK/mTOR/NF-κB pathway. However, FA alone is hard to completely restore KD into normal condition. In conclusion, FA has potential protective effects on KD, suggesting its promising role as an adjuvant for KD therapy in the future.

CREB1 Silencing Protects Against Inflammatory Response in Rats with Deep Vein Thrombosis Through Reducing RPL9 Expression and Blocking NF-κB Signaling.

Apoptosis and inflammation of vascular endothelial cells (VECs) are the most important causes of deep vein thrombosis (DVT). cAMP response element binding protein 1 (CREB1) encodes a transcription factor that binds as a homodimer to the cAMP-responsive element and can promote inflammation. CREB1 is found to be upregulated in the plasma of patients with venous thromboembolism. However, the biological functions of CREB1 in DVT remain unknown. We evaluated the effect of CREB1 in a rat model of inferior vena cava (IVA) stenosis-induced DVT. IVC stenosis resulted in stable thrombus, inflammatory response and CREB1 upregulation, whereas CREB1 knockdown inhibited thrombus and inflammation in DVT rats. In vitro analysis showed that CREB1 knockdown inhibited VEC apoptosis. Mechanistically, CREB1 knockdown reduced Ribosomal protein L9 (RPL9) expression and blocked the NF-κB pathway. Therefore, CREB1 may become a potential therapeutic target of DVT prevention.

Programmed Cell Death Protein 2-like Promotes Inflammation and Oxidative Stress in Vascular Endothelial Cells.

Programmed cell death protein 2-like (PDCD2L) is a shuttle protein of the nucleus and cytoplasm and is related to the ribosome biogenesis. However, there are few reports on the relationship between PDCD2L and inflammation, and the exact relationship between PDCD2L and inflammation has not been determined in vascular endothelial cells yet. Accordingly, we focus on exploring the relationship between PDCD2L and inflammation and its potential mechanisms. Our research findings suggested that PDCD2L is a proinflammatory target. The result showed that, by interfering with the expression of PDCD2L, LPS-induced inflammation of vascular endothelial cells can be reduced, such as IL-6 and IL-1β, as well as the adhesion factor ICAM1. Meanwhile, overexpression of PDCD2L can further increase LPS-induced inflammation levels, ICAM1, and ROS production, reduce CAT, GSH/GSSG levels, and increase SOD levels. Therefore, we determined that PDCD2L has a regulatory effect on inflammation and oxidative stress of vascular endothelial cells, and its regulatory mechanism may be related to inflammatory transcription factors STAT1, NF-κB regulation, transport of inflammatory messenger mRNA, and ribosome biogenesis. Then, we screened that andrographolide (Andro) can bind to PDCD2L, thus inhibiting inflammation and endothelial cell adhesion caused by the overexpression of PDCD2L. This study reveals that PDCD2L is a potential anti-inflammatory therapeutic target, providing new exploration for the development of anti-inflammatory drugs.

FOXP1‑induced DUSP12 alleviates vascular endothelial cell inflammation and oxidative stress injury induced by ox‑LDL via MAP3K5 signaling pathway.

Atherosclerosis (AS) is a type of chronic inflammatory disease and the main pathological basis of cardiovascular and cerebrovascular diseases, which seriously threaten the health of patients. The dual specificity phosphatase 12 (DUSP12) protein is known as regulator of inflammatory diseases. Nonetheless, at present, there are only a few reports on the regulatory role of DUSP12 in AS. Human umbilical vein endothelial cells (HUVECs) were induced using oxidized low-density lipoprotein (ox-LDL). Subsequently, cell transfection experiments were performed to overexpress DUSP12 in ox-LDL-induced HUVECs. Cell Counting Kit-8, TUNEL western blotting, 2',7'-dichlorofluorescein diacetate assays, ELISA and other techniques were used to measure cell viability, apoptosis, inflammation, oxidative stress and endothelial function-related indicators. Subsequently, the relationship between DUSP12 and Forkhead box P1 (FOXP1) was predicted using the JASPAR database and verified using luciferase reporter and chromatin immunoprecipitation assays. Finally, the regulatory mechanism was investigated by simultaneously overexpressing DUSP12 and knocking down FOXP1 in ox-LDL-induced HUVECs and MAP3K5-related proteins of the DUSP12 downstream pathway were measured by western blotting. The expression of DUSP12 in ox-LDL-induced HUVECs was significantly decreased. Overexpression of DUSP12 inhibited apoptosis, inflammation and oxidative stress damage and alleviated endothelial dysfunction in ox-LDL-induced HUVECs. FOXP1 promoted the transcription of DUSP12. Moreover, FOXP1 alleviated ox-LDL-induced apoptosis, inflammation and oxidative stress damage in HUVECs by regulating the expression of DUSP12, probably acting through the MAP3K5 pathway. Collectively, the present study revealed that FOXP1-induced DUSP12 alleviated vascular endothelial cell inflammation and oxidative stress injury in ox-LDL-induced HUVECs via the MAP3K5 signaling pathway, which might shed novel insights into the targeted treatment for AS in the clinic.

Suppression of Inflammatory Cytokine Genes Expression in Vascular Endothelial Cells by Super-low Dose Lipopolysaccharide-activated Macrophages.

Vascular endothelial cells play an important role in regulating immune responses and in keeping the balance between blood coagulation and fibrinolysis. Inflammatory cytokines produced by activated macrophages and vascular endothelial cells excessively activate vascular endothelial cells, leading to an imbalance in the expression of blood coagulation- and fibrinolysis-related factors. The dysfunction of vascular endothelial cells can lead to development of various diseases. In a previous study the increased expression of inflammatory cytokines in adipocytes was shown to be suppressed by the culture medium of macrophages activated by low-dose lipopolysaccharide (LPS). Suppressing inflammatory cytokine gene expression of low-dose LPS-activated macrophages may allow for the regulation of the dysfunction in vascular endothelial cells. Human monocytes THP-1 cells were differentiated into macrophages with phorbol 12-myristate 13-acetate (PMA) and were activated with LPS. The culture medium of the LPS-activated THP-1 was added to human aortic endothelial cells (HAoEC). After five days, the expression of inflammatory cytokine genes interleukin (IL)1B, IL6, IL8, and tumor necrosis factor (TNF)A, blood coagulation-related genes SERPINE1, tissue factor (TF), and thrombopoietin (TM), and fibrinolysis-related gene tissue-type plasminogen activator (t-PA) was analyzed using quantitative real-time PCR. IL1B, IL8, SERPINE1, TF, and TM expression in HAoEC was significantly reduced in the culture medium of super-low dose (0.1 ng/ml) LPS-activated macrophages. Super-low dose LPS-activated macrophages can suppress vascular endothelial cell inflammation and may be useful in preventing various diseases caused by the dysfunction of activated vascular endothelial cells.

Sirt6 inhibits vascular endothelial cell pyroptosis by regulation of the Lin28b/let-7 pathway in atherosclerosis

Our previous study showed that Sirtuin 6 (Sirt6) plays an important role in the regulation of vascular endothelial cell inflammation. Recently, studies have reported that the RNA binding protein Lin28b directly regulates the let-7 microRNA (miRNA), which participates in the process of atherosclerosis (AS) by regulating inflammation. Pyroptosis is a form of programmed cell death that is accompanied by inflammation and is critical for AS. Thus, this study aimed to investigate the role of Sirt6 and Lin28b in vascular endothelial cell pyroptosis and the related mechanism. The present study showed that Lin28b expression was upregulated in the aortic intima and aorta of apolipoprotein E knockout (ApoE-/-) mice fed with a high-fat diet (HFD) for 8 or 12 weeks. Then, in vitro study found Lin28b was involved in tumor necrosis factor-α (TNF-α)-induced vascular endothelial cell pyroptosis, as indicated by the increased number of PI-positive cells and gasdermin D (GSDMD) cleavage, as well as the increased release of lactate dehydrogenase (LDH) and interleukin (IL)-1β. Further studies demonstrated that TNF-α significantly decreased the expression of let-7, while Lin28b knockdown significantly increased the expression of let-7a, let-7d and let-7g. In addition, Sirt6 overexpression decreased Lin28b expression. Moreover, Sirt6 overexpression suppressed pyroptosis by decreasing the number of PI-positive cells and GSDMD cleavage, as well as by decreasing the release of LDH and IL-1β in TNF-α-induced vascular endothelial cells. Further mechanistic studies revealed that Sirt6 directly interacted with and deacetylated Lin28b. Taken together, these findings indicate that Sirt6 inhibits vascular endothelial cell pyroptosis by negatively regulating the Lin28b/let-7 pathway in AS.

Curcumin attenuates inflammation of Macrophage-derived foam cells treated with Poly-L-lactic acid degradation via PPAR\u03b3 signaling pathway

Poly-L-lactic acid (PLLA) is considered to be a promising candidate material for biodegradable vascular scaffolds (BVS) in percutaneous coronary intervention (PCI). But, PLLA-BVS also faces the challenge of thrombosis (ST) and in-stent restenosis (ISR) caused by in-stent neo-atherosclerosis (ISNA) associated with inflammatory reactions in macrophage-derived foam cells. Our previous studies have confirmed that curcumin alleviates PLLA-induced injury and inflammation in vascular endothelial cells, but it remains unclear whether curcumin can alleviate the effect of inflammatory reactions in macrophage-derived foam cells while treated with degraded product of PLLA. In this study, PLLA-BVS was implanted in the porcine coronary artery to examine increased macrophages and inflammatory cytokines such as NF-κb and TNF-α by histology and immunohistochemistry. In vitro, macrophage-derived foam cells were induced by Ox-LDL and observed by Oil Red Staining. Foam cells were treated with pre-degraded PLLA powder, curcumin and PPARγ inhibitor GW9662, and the expression of IL-6, IL-10, TNF-α, NF-κb, PLA2 and PPARγ were investigated by ELISA or RT-qPCR. This study demonstrated that the macrophages and inflammatory factors increased after PLLA-BVS implantation in vivo, and foam cells derived from macrophages promoted inflammation by products of PLLA degradation in vitro. This present study was found that the inflammation of foam cells at the microenvironment of PLLA degraded products were significantly increased, and curcumin can attenuate the inflammation caused by the PLLA degradation via PPARγ signal pathway. In addition, curcumin should be further studied experimentally in vivo experiments on animal models as a potential therapeutic to reduce ISNA of PLLA-BVS.Graphical abstract

Astragalus Polysaccharides Reduce High-glucose-induced Rat Aortic Endothelial Cell Senescence and Inflammasome Activation by Modulating the Mitochondrial Na+/Ca2+ Exchanger.

Vascular endothelial cells play a vital role in atherosclerotic changes and the progression of cardiovascular disease in older adults. Previous studies have indicated that Astragalus polysaccharides (APS), a main active component of the traditional Chinese medicine Astragalus, protect mitochondria and exert an antiaging effect in the mouse liver and brain. However, the effect of APS on rat aortic endothelial cell (RAEC) senescence and its underlying mechanism have not been investigated. In this study, we extracted RAECs from 2-month-old male Wistar rats by the tissue explant method and found that APS ameliorated the high-glucose-induced increase in the frequency of SA-β-Gal positivity and the levels of the senescence-related proteins p16, p21, and p53. APS increased the tube formation capacity of RAECs under high-glucose conditions. Moreover, APS enhanced the expression of the mitochondrial Na+/Ca2+ exchanger NCLX, and knockdown of NCLX by small interfering RNA (siRNA) transfection suppressed the antiaging effect of APS under high-glucose conditions. Additionally, APS ameliorated RAEC mitochondrial dysfunction, including increasing ATP production, cytochrome C oxidase activity and the oxygen consumption rate (OCR), and inhibited high-glucose-induced NLRP3 inflammasome activation and IL-1β release, which were reversed by siNCLX. These results indicate that APS reduces high-glucose-induced inflammasome activation and ameliorates mitochondrial dysfunction and senescence in RAECs by modulating NCLX. Additionally, APS enhanced the levels of autophagy-related proteins (LC3B-II/I, Atg7) and increased the quantity of autophagic vacuoles under high-glucose conditions. Therefore, these data demonstrate that APS may reduce vascular endothelial cell inflammation and senescence through NCLX.

Long noncoding RNA HULC is an independent predictor of COVID-19 severity and mortality in relation to microRNA-9 and IL-6

&lt;abstract&gt; &lt;p&gt;LncRNA HULC regulates inflammation in vascular endothelial cells resulting in their dysfunction. Endothelial dysfunction contributes to severe COVID-19. lncRNA HULC targets miRNA-9 that play roles in the pathogenesis and progression of COVID-19 through the acute inflammatory response mediated by IL-6. This study aimed to evaluate the role of lncRNA HULC, miRNA-9, and IL-6 in estimating the severity and predicting the prognosis of COVID-19. There were 38 non-severe, 38 severe COVID-19 patients, and 38 healthy controls enrolled in this study. Expression of lncRNA HULC and miRNA-9 was performed using RT-qPCR. ELISA was utilized to measure serum IL-6. Expression of lncRNA HULC and IL-6 level were increased in severe patients compared to non-severe patients and controls (p &amp;lt; 0.001). MiRNA-9 showed the lowest expression levels in the severe patients in comparison with non-severe patients and controls (p &amp;lt; 0.001) lncRNA HULC was negatively correlated with miRNA-9 (p &amp;lt; 0.001, r = −0.582) and positively correlated with IL-6 (p &amp;lt; 0.001, r = 0.567). Furthermore, miRNA-9 showed a negative correlation with IL-6 (p &amp;lt; 0.001, r = −0.0466). For severity prediction, lncRNA HULC expression had an adjusted OR of 52.5 (95% CI: 1.43−192.2, p = 0.031). The lncRNA HULC had an adjusted mortality hazard ratio of 1.9 (95% CI: 1.02−3.56, p = 0.043) after the adjustment of IL-6. So, in COVID-19 patients, the lncRNA HULC had a positive correlation with IL-6 and a negative correlation with miRNA-9. The COVID-19 severity and mortality appear to be predicted independently by the lncRNA HULC.&lt;/p&gt; &lt;/abstract&gt;

Pitavastatin maintains MAPK7 expression and alleviates angiotensin II-induced vascular endothelial cell inflammation and injury.

Statins have been reported to suppress vascular remodeling in rats with spontaneous hypertension. However, the possible effects of the statin pitavastatin on hypertension-induced endothelial inflammation and injury remain to be fully elucidated. The present study aimed to evaluate the effects of pitavastatin on HUVEC injury and inflammation. HUVECs were exposed to angiotensin (Ang) II with or without pitavastatin co-treatment, after which MAPK7 expression was detected via reverse transcription-quantitative PCR and western blotting. MAPK7 expression was additionally silenced in HUVECs via transfection with short hairpin RNA, followed by Ang II treatment with or without pitavastatin. Cell viability, inflammation, reactive oxygen species (ROS) production, nitric oxide (NO) production and cell apoptosis were then measured by using Cell Conting Kit-8, ELISA, commercial corresponding kits and TUNEL staining, respectively. Western blotting was also used to determine the protein expression of endothelial NO synthase and endothelin 1, and the proteins involved in apoptosis. Results of the present study demonstrated that the expression levels of MAPK7 in Ang II-induced endothelial cells were decreased, which was reversed following treatment with pitavastatin. Pitavastatin reversed the Ang II-induced reduction in cell viability and reversed the Ang II-induced increase in inflammatory factor and ROS levels and apoptosis in HUVECs by activating MAPK7. Treatment with pitavastatin also increased the production of NO in addition to increasing the expression of endothelial NO synthase and endothelin-1 in Ang II-induced HUVECs through MAPK7 activation. Collectively, results from the present study demonstrated that treatment with pitavastatin preserves MAPK7 expression to alleviate Ang II-induced vascular endothelial cell inflammation and injury. Therefore, findings of the present study may help to elucidate the mechanisms underlying the effects of pitavastatin on vascular endothelial cell inflammation and injury.

Abstract 10926: Importance of Mitochondrial DNA Damage in Cigarette Smoke Extract-Induced Activation of Innate Immune System

Objective: Smoking is a well-known risk factor for atherosclerosis, yet the mechanism by which smoking causes atherosclerosis remains unclear. It has been reported that inflammation and DNA damage are involved in the formation and development of atherosclerosis. We have previously reported that nuclear DNA damage was increased in peripheral mononuclear cells of smokers compared to those of non-smokers, and that DNA damage was accumulated in atherosclerotic lesions. In this study, to clarify the mechanism by which smoking induces inflammation in vascular endothelial cells, we investigated the effect of cigarette smoke extract (CSE) on both nuclear and mitochondrial DNA damage and the subsequent cellular response in human umbilical vein endothelial cells (HUVEC). Methods and Results: CSE increased double-strand breaks in HUVEC. Notably, this increase was detected relatively late (after 3 days of CSE exposure) compared to other genotoxic agents. CSE also increased oxidative DNA damage both in the nucleus and mitochondria and induced mitochondrial dysfunction. Mitochondrial dysfunction decreased cytosolic protein levels of ICAD, an inhibitor of caspase-activated DNase (CAD), which causes nuclear DNA fragmentation, and increased CAD in the nucleus, suggesting that this is one of the mechanisms of nuclear DNA double-strand breaks. In addition, continuous stimulation by CSE induced the accumulation of cytosolic DNA. Interestingly, real-time PCR analysis revealed that the accumulated DNA in the cytosol was derived not only from the nucleus but also from mitochondria. We further examined whether DNA accumulated in the cytosol activated cytosolic DNA-sensing pathways. The production of cGAMP, a second messenger in cGAS (a DNA-sensing receptor) signaling, was increased by CSE. We also found that the mRNA expression of IL-6 was increased by CSE, and that the increase was suppressed by si-cGAS. Conclusions: This study showed that continuous exposure to CSE induces not only nuclear but also mitochondrial DNA damage, which leads to cytosolic DNA accumulation, and evokes chronic inflammation via the cGAS-STING pathway.

Anti-inflammatory Effect of Salvia Miltiorrhiza is Mediated via IL-6, JAK, and STAT Pathway in a Dysfunctional Vascular Endothelial Cell

The vascular complication of diabetes mellitus is a problem for the patient, and the ability to cope with the disease and the associated inflammation is a critical aspect of diabetes. Cytokines-induced inflammation in vascular endothelial cells (VECs) plays an active role in chronic diseases such as atherosclerosis, diabetes mellitus, kidney injury, and stroke. We investigated the role of total salvianolic acids (TSA), total tanshinones (TTSN), and their combination (TSA/TTSN) on the activated vascular endothelial cell and its inhibitory effect on signal transduction and cytokines regulation. In the extracellular medium of the injury model of human umbilical vein endothelial cells (HUVECs) induced by thrombin, the human IL-6, VCAM-1, and ICAM-1 were significantly elevated (p ˂ 0.05). However, suppression in the TSA, TTSN, and TSA/TTSN (100 µg/L)-treated groups (p &gt; 0.05) were notable. TSA alone but not TTSN and TSA/TTSN combination, inhibited the expression of P-selectin (p &lt; 0.05) and E-selectin (p &lt; 0.01) respectively, in VECs. Western blot analysis showed JAK and STAT expression in VECs however, the protein expression was modest in the Salvia miltiorrhiza-treated groups, indicating the potential of TSA/TTSN in the inflammatory pathways of IL-6, JAK, and STAT signal transduction in endothelial cells (ECs). This study has made novel observations regarding the components of Salvia miltiorrhiza regulatory effect on cytokines in Vascular Biology. Keywords: Atherosclerosis; Cytokines; Diabetes mellitus; HUVECs; Inflammation; Salvia militiorrhiza.

CIGARETTE SMOKE EXTRACT INDUCES DNA DAMAGE AND ACCELERATES CELLULAR SENESCENCE IN HUMAN ENDOTHELIAL CELLS

Abstract Objective: Elevated blood pressure and tobacco smoking are causes of preventable mortality. The effects of tobacco smoking on blood pressure are complex and chronic effects of tobacco smoking are inconsistent. We reported that DNA damage was increased in smokers’ blood cells compared to non-smokers. Recently, it has been reported that DNA damage is involved in cellular senescence. In this study, we investigated whether cigarette smoke extract (CSE) exerts DNA damage and cellular senescence in endothelial cells and the physiological influence of DNA damage. Design and method: The effect of CSE extracted from tobacco smoke was examined in human umbilical vein endothelial cells (HUVEC). CSE was added to HUVEC and DNA damage formation was quantified by fluorescence immunostaining; DNA single strand breaks (SSBs) with RPA 2 and double-strand breaks (DSBs) with phosphorylated histone H2AX as indices. Cellular senescence was quantified by senescence-associated -b galactosidase activity. The mRNA expression of inflammatory cytokines was quantified by real-time RT PCR. Results: SSBs increased at 24 hours after CSE stimulation, and DSBs increased significantly at 72 hours after stimulation. Continuous stimulation with CSE for 7 days resulted in an accumulation of cytosolic DNA (percentage of cells with cytosolic DNA; control: 3.4 ± 1.1, 7 days stimulation: 11.8 ± 1.8, p &lt; 0.01)and accelerated cellular senescence (percentage of senescent cells; control: 32.5 ± 3.4, 7 days stimulation: 61.5 ± 5.2, p &lt; 0.01). The mRNA expression of inflammatory cytokines, such as IL-6 and IL-1a was increased and prolonged by continuous CSE stimulation. Conclusions: CSE was shown to induce DNA damage, accumulation of cytosolic DNA, cellular senescence and inflammation of vascular endothelial cells.

5-HT2A Receptor and 5-HT Degradation Play a Crucial Role in Atherosclerosis by Modulating Macrophage Foam Cell Formation, Vascular Endothelial Cell Inflammation, and Hepatic Steatosis.

Aim: Previously, we found that diabetes-related liver dysfunction is due to activation of the 5-HT 2A receptor (5-HT 2A R) and increased synthesis and degradation of 5-HT. Here, we investigated the role of 5-HT in the development of atherosclerosis. Methods: The study was conducted using high-fat diet-fed male ApoE −/− mice, THP-1 cell-derived macrophages, and HUVECs. Protein expression and biochemical indexes were determined by Western blotting and quantitative analysis kit, respectively. The following staining methods were used: oil red O staining (showing atherosclerotic plaques and intracellular lipid droplets), immunohistochemistry (showing the expression of 5-HT 2A R, 5-HT synthase, and CD68 in the aortic wall), and fluorescent probe staining (showing intracellular ROS). Results: In addition to improving hepatic steatosis, insulin resistance, and dyslipidemia, co-treatment with a 5-HT synthesis inhibitor and a 5-HT 2A R antagonist significantly suppressed the formation of atherosclerotic plaques and macrophage infiltration in the aorta of ApoE −/− mice in a synergistic manner. Macrophages and HUVECs exposed to oxLDL or palmitic acid in vitro showed that activated 5-HT 2A R regulated TG synthesis and oxLDL uptake by activating PKCε, resulting in formation of lipid droplets and even foam cells; ROS production was due to the increase of both intracellular 5-HT synthesis and mitochondrial MAO-A-catalyzed 5-HT degradation, which leads to the activation of NF-κB and the release of the inflammatory cytokines TNF-α and IL-1β from macrophages and HUVECs as well as MCP-1 release from HUVECs. Conclusion: Similar to hepatic steatosis, the pathogenesis of lipid-induced atherosclerosis is associated with activation of intracellular 5-HT 2A R, 5-HT synthesis, and 5-HT degradation.

Amorphous silica nanoparticles induce inflammation via activation of NLRP3 inflammasome and HMGB1/TLR4/MYD88/NF-kb signaling pathway in HUVEC cells

Silica nanoparticles (SiO2 NPs) are extensively applied in various field, which increased their health risks to humans. SiO2 NPs were reported to enter into blood through inhalation and meanwhile, the potential use of SiO2 NPs as drug carriers in vivo allows them to present in blood circulation to induce inflammation of vascular endothelial cells which can be closely related with cardiovascular diseases, whilst the intrinsic mechanism has not been well understood. In this study, we found a regulation of signal axis induced by amorphous SiO2 NPs that triggers pro-inflammatory responses in human umbilical vein endothelial cells (HUVECs). HUVECs exposed with SiO2 NPs generate excess amount of reactive oxygen species (ROS) and lactate dehydrogenase (LDH), together with the up-regulation of cell inflammatory factors [interleukin-1 beta (IL-1β), interleukin-6 (IL-6), tumor necrotic factor-α (TNF-α)] and cell adhesion molecules [intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1)]. In addition, SiO2 NPs were found to promote the translocation and release of high-mobility group box 1 (HMGB1) from nucleus to cytoplasm, which was demonstrated to be regulated by ROS and NOD-like receptor pyrin domain containing 3 (NLRP3) inflammasome. Subsequently, toll-like receptor 4 (TLR4) could bind with HMGB1, up-regulate the expression of myeloid differentiation factor 88 (MyD88) and then activate nuclear factor kappa-B (NF-κB) signaling pathway, ultimately induced the inflammatory response of HUVECs. Overall, out results revealed the related signaling pathways of cell inflammation induced by amorphous SiO2 NPs, which provided new insights in understanding SiO2 NPs-induced cytotoxicity and offered safety guidance for further nanomaterial application.