Neutrophil Extracellular Traps: Potential Prothrombotic State Markers and Therapeutic Targets for Atrial Fibrillation.

BACKGROUND: Recently, the mechanism of thrombogenesis has taken a new direction with the involvement of neutrophil extracellular traps (NETs). However, little is known about the relationship between NETs and thrombogenesis in atrial fibrillation (AF). OBJECTIVE: Our study aimed to evaluate NETs in AF patients and their potential association with thrombogenesis. In addition, we studied the effect of NETs on thrombogenesis in rat models. METHODS: A total of 125 AF patients and 172 controls were studied. Spontaneous echo contrast (SEC) was examined using transesophageal echocardiography to assess the prothrombotic state. We used rapid atrial pacing (RAP) rat models to study NETs' formation and their effects on thrombogenesis. The levels of NETs were analyzed by flow cytometry. To deeply understand the regulatory mechanism of NET formation, the transcriptional characteristics of the left atrial appendage (LAA) tissue from RAP rats were analyzed. RESULTS: We found that NETs were increased significantly in AF patients and positively correlated with SEC grades. And inserting the NET level could significantly enhance the predictivity of CHA2DS2-VASc scores for the AF prothrombotic state. In the RAP models, we observed that NET levels increased significantly in the LAA and promoted thrombosis. Meanwhile, we found that these changes could be suppressed by the NET formation inhibitor. Transcriptomic analysis of the LAA tissue from RAP rats suggested that RAP might stimulate the NET formation by promoting the expression of inflammatory cytokine and adhesion genes. CONCLUSION: NETs may constitute useful thrombogenesis risk markers in AF patients and provide a potential therapeutic strategy for AF management.

Galangin reduces vascular endothelial cell dysfunction via Heme oxygenase-1 signaling.

OBJECTIVE: As one of the independent risk factors for atherosclerosis (AS), oxidized low-density lipoprotein (ox-LDL) can trigger damage to the vascular intima and induce the expression of various adhesion molecules. This study aimed to explore the effects of galangin, an extract of galangal, on ox-LDL-induced vascular endothelial cells. METHODS: The effects of different concentrations of galangin or ox-LDL on the metabolic activity of vascular endothelial cells were determined using the CCK8 assay. Afterward, the role of galangin in the expression levels of inflammatory factors was assessed using RT-qPCR and Western blotting. In addition, the influences of galangin on apoptosis and endothelial-mesenchymal transition (EndMT) were also evaluated. Through molecular docking, the Heme oxygenase-1 (HO-1) signaling pathway was proposed, and then the effects of the HO-1 signaling pathway on the regulatory roles of galangin were evaluated. RESULTS: In this study, galangin was found to effectively increase the metabolic activity of ox-LDL-induced cells in a concentration-dependent manner. In addition, galangin was found to reduce ox-LDL-induced cell inflammation, apoptosis, and EndMT. Moreover, galangin could combine with HO-1 and regulate the HO-1 signaling pathway. The effects of galangin on cells were shown to be through the HO-1 signaling pathway. CONCLUSION: To sum up, galangin reduced ox-LDL-induced inflammation, apoptosis, and EndMT of vascular endothelial cells via regulating the HO-1 signaling pathway.

Itaconate regulates macrophage function through stressful iron-sulfur cluster disrupting and iron metabolism rebalancing.

Lipopolysaccharide (LPS)-stimulated macrophages express an aconitate decarboxylase (IRG1, also called ACOD1), leading to accumulation of the endogenous metabolite itaconate. However, the precise mechanisms by which elevated itaconate levels alter macrophage function are not clear. Our hypothesis is itaconate affects macrophage function through some uncertain mechanism. Based on this, we established a transcriptional and proteomic signature of macrophages stimulated by itaconate and identified the pathways of IL-1ß secretion and altered iron metabolism. Consistently, the effect of IRG1 deficiency on IL-1ß secretion and iron metabolism was confirmed in IRG1 knockout THP-1 cell lines. Several common inhibitors and other compounds were used to examine the molecular mechanisms involved. Only cysteine and antioxidants (catechin hydrate) could inhibit caspase-1 activation and IL-1ß secretion in itaconate-stimulated macrophages. We further found that aconitase activity was decreased by itaconate stimulation. Our results demonstrate the counteracting effects of overexpression of mitochondrial aconitase (ACO2, a tricarboxylic acid cycle enzyme) or cytosolic aconitase (ACO1, an iron regulatory protein) on IL-1ß secretion and altered iron metabolism. Both enzyme activities were inhibited by itaconate because of iron-sulfur (Fe-S) cluster destruction. Our findings indicate that the immunoregulatory functions of IRG1 and itaconate in macrophages are stressful Fe-S cluster of aconitases disrupting and iron metabolism rebalancing.

Naringin protects endothelial cells from apoptosis and inflammation by regulating the Hippo-YAP Pathway.

Atherosclerosis is the primary cause of several cardiovascular diseases. Oxidized low-density lipoprotein (ox-LDL)-induced apoptosis, endothelial-mesenchymal transition (EndMT), and inflammation are crucial for the progression of cardiovascular diseases, including atherosclerosis. Naringin, a major compound from tomatoes, grapefruits, and related citrus, reportedly exhibits potential protective effects during atherosclerosis development; however, its effect on ox-LDL-induced human umbilical vein endothelial cell (HUVEC) damage remains unknown. In the present study, we investigated the anti-apoptotic and anti-inflammatory activities of naringin against ox-LDL-induced endothelial cells, and the underlying mechanism. Naringin pretreatment significantly and concentration-dependently inhibited ox-LDL-induced cell injury and apoptosis. Additionally, naringin restored endothelial barrier integrity by preventing VE-cadherin disassembly and F-actin remodeling, and down-regulated pro-inflammatory factors like IL-1ß, IL-6, and IL-18, in the HUVECs. We also demonstrated that naringin treatment restored ox-LDL-induced YAP (yes-associated protein) down-regulation, given the YAP-shRNA attenuated cytoprotective effect of naringin on ox-LDL-induced endothelial cell injury and apoptosis. Collectively, our data indicate that naringin reversed ox-LDL-triggered HUVEC apoptosis, EndMT, and inflammation by inhibiting the YAP pathway. Therefore, naringin may have a therapeutic effect on endothelial injury-related disorders.

The immune functions of PCSK9: Local and systemic perspectives.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) binds to low-density lipoprotein receptor (LDLR) to trigger endocytosis and lysosome degradation in hepatocytes, regulating intracellular and plasma cholesterol levels. The discovery of PCSK9 has provided a new target for the management of hypercholesterolemia and cardiovascular risk reduction. There is emerging evidence that shows that PCSK9 may influence the activity of various cell types through either LDLR-dependent or LDLR-independent mechanisms. Changes in the circulating PCSK9 levels have been observed during infection and proinflammatory conditions. Furthermore, PCSK9 as a secreted protein has both local and systemic effects on cellular function. In this review, we summarize the roles of PCSK9 in inflammation.

ApoA-I induces S1P release from endothelial cells through ABCA1 and SR-BI in a positive feedback manner

Sphingosine-1-phosphate (S1P), which has emerged as a pivotal signaling mediator that participates in the regulation of multiple cellular processes, is derived from various cells, including vascular endothelial cells. S1P accumulates in lipoproteins, especially HDL, and the majority of free plasma S1P is bound to HDL. We hypothesized that HDL-associated S1P is released through mechanisms associated with the HDL maturation process. ApoA-I, a major HDL apolipoprotein, is a critical factor for nascent HDL formation and lipid trafficking via ABCA1. Moreover, apoA-I is capable of promoting bidirectional lipid movement through SR-BI. In the present study, we confirmed that apoA-I can facilitate the production and release of S1P by HUVECs. Furthermore, we demonstrated that ERK1/2 and SphK activation induced by apoA-I is involved in the release of S1P from HUVECs. Inhibitor and siRNA experiments showed that ABCA1 and SR-BI are required for S1P release and ERK1/2 phosphorylation induced by apoA-I. However, the effects triggered by apoA-I were not suppressed by inhibiting ABCA1/JAK2 or the SR-BI/Src pathway. S1P released due to apoA-I activation can stimulate the (ERK1/2)/SphK1 pathway through S1PR (S1P receptor) 1/3. These results indicated that apoA-I not only promotes S1P release through ABCA1 and SR-BI but also indirectly activates the (ERK1/2)/SphK1 pathway by releasing S1P to trigger their receptors. In conclusion, we suggest that release of S1P induced by apoA-I from endothelial cells through ABCA1 and SR-BI is a self-positive-feedback process: apoA-I-(ABCA1 and SR-BI)-(S1P release)-S1PR-ERK1/2-SphK1-(S1P production)-(more S1P release induced by apoA-I) (AU)

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ApoA-I induces S1P release from endothelial cells through ABCA1 and SR-BI in a positive feedback manner.

Sphingosine-1-phosphate (S1P), which has emerged as a pivotal signaling mediator that participates in the regulation of multiple cellular processes, is derived from various cells, including vascular endothelial cells. S1P accumulates in lipoproteins, especially HDL, and the majority of free plasma S1P is bound to HDL. We hypothesized that HDL-associated S1P is released through mechanisms associated with the HDL maturation process. ApoA-I, a major HDL apolipoprotein, is a critical factor for nascent HDL formation and lipid trafficking via ABCA1. Moreover, apoA-I is capable of promoting bidirectional lipid movement through SR-BI. In the present study, we confirmed that apoA-I can facilitate the production and release of S1P by HUVECs. Furthermore, we demonstrated that ERK1/2 and SphK activation induced by apoA-I is involved in the release of S1P from HUVECs. Inhibitor and siRNA experiments showed that ABCA1 and SR-BI are required for S1P release and ERK1/2 phosphorylation induced by apoA-I. However, the effects triggered by apoA-I were not suppressed by inhibiting ABCA1/JAK2 or the SR-BI/Src pathway. S1P released due to apoA-I activation can stimulate the (ERK1/2)/SphK1 pathway through S1PR (S1P receptor) 1/3. These results indicated that apoA-I not only promotes S1P release through ABCA1 and SR-BI but also indirectly activates the (ERK1/2)/SphK1 pathway by releasing S1P to trigger their receptors. In conclusion, we suggest that release of S1P induced by apoA-I from endothelial cells through ABCA1 and SR-BI is a self-positive-feedback process: apoA-I-(ABCA1 and SR-BI)-(S1P release)-S1PR-ERK1/2-SphK1-(S1P production)-(more S1P release induced by apoA-I).

Ultrasound-driven secondary self-assembly of amphiphilic ß-cyclodextrin dimers.

The controlled secondary self-assembly of amphiphilic molecules in solution is theoretically and practically significant in amphiphilic molecular applications. An amphiphilic ß-cyclodextrin (ß-CD) dimer, namely LA-(CD)2 , has been synthesized, wherein one lithocholic acid (LA) unit is hydrophobic and two ß-CD units are hydrophilic. In an aqueous solution at room temperature, LA-(CD)2 self-assembles into spherical micelles without ultrasonication. The primary micelles dissociates and then secondarily form self-assemblies with branched structures under ultrasonication. The branched aggregates revert to primary micelles at high temperature. The ultrasound-driven secondary self-assembly is confirmed by transmission electron microscopy, dynamic light scattering, (1) H NMR spectroscopy, and Cu(2+) -responsive experiments. Furthermore, 2D NOESY NMR and UV/Vis spectroscopy results indicate that the formation of the primary micelles is driven by hydrophilic-hydrophobic interactions, whereas host-guest interactions promote the formation of the secondary assemblies. Additionally, ultrasonication is shown to be able to effectively destroy the primary hydrophilic-hydrophobic balances while enhancing the host-guest interaction between the LA and ß-CD moieties at room temperature.

Hydrogen sulfide prevents H2O2-induced senescence in human umbilical vein endothelial cells through SIRT1 activation.

The aim of the present study was to investigate the attenuation of endothelial cell senescence by H2S and to explore the mechanisms underlying the anti-aging effects of H2S. Senescence was induced in human umbilical vein endothelial cells (HUVECs) by incubation in 25 µmol/l H2O2 for 1 h. Senescence-associated ß-galactosidase (SA-ß-gal) activity was examined to determine the effects of H2S on senescent HUVECs. The results indicated that SA-ß-gal activity in the H2O2-treated HUVECs was 11.2 ± 1.06%, which was attenuated in the NaHS group. Pretreatment with nicotinamide (NAM), a sirtuin 1 (SIRT1) inhibitor, inhibited the reduction in senescence associated with H2S. Immunoblot analyses revealed that SIRT1 levels in senescent HUVECs treated with NaHS (60 µM) were indistinguishable from controls; however, analyses of SIRT1 activity indicated that SIRT1 enzyme activity was enhanced. In addition, we found that H2S improves the function of senescent HUVECs. The present study demonstrated that H2S protects against HUVEC senescence, potentially through modulation of SIRT1 activity. Furthermore, this study establishes a novel endothelial protective effect of H2S.

HDL drug carriers for targeted therapy.

Plasma concentrations of high-density lipoprotein cholesterol (HDL-C) are strongly and inversely associated with cardiovascular risk. HDL is not a simple lipid transporter, but possesses multiple anti-atherosclerosis activities because it contains special proteins, signaling lipid, and microRNAs. Natural or recombinant HDLs have emerged as potential carriers for delivering a drug to a specified target. However, HDL function also depends on enzymes that alter its structure and composition, as well as cellular receptors and membrane micro-domains that facilitate interactions with the microenvironment. In this review, four mechanisms predicted to enhance functions or targeted therapy of HDL in vivo are discussed. The first involves caveolae-mediated recruitment of HDL signal to bind their receptors. The second involves scavenger receptor class B type I (SR-BI) mediating anchoring and fluidity for signal-lipid of HDL. The third involves lecithin-cholesterol acyltransferase (LCAT) concentrating the signaling lipid at the surface of the HDL particle. The fourth involves microRNAs (miRNAs) being delivered in the blood to special targets by HDL. Exploitation of these four mechanisms will promote HDL to carry targeted drugs and increase HDL's clinical value.

Hydrogen sulfide inhibits macrophage-derived foam cell formation.

Recent evidence indicates that hydrogen sulfide (H(2)S) exerts an antiatherogenic effect, but the mechanism is unclear. Formation of macrophage-derived foam cells is a crucial event in the development of atherosclerosis. Thus, we explore the effect of H(2)S on the formation of macrophage-derived foam cells. Incubation of monocyte-derived macrophages with oxidized LDL (oxLDL) alone caused significant increases both in intracellular lipids revealed by Oil-red O staining and in intracellular total cholesterol (TC) and esterified cholesterol (EC) concentrations assessed by high-performance liquid chromatography. Sodium hydrosulfide (NaHS, an H(2)S donor) remarkably abrogated oxLDL-induced intracellular lipid accumulation, and attenuated TC and EC concentrations and EC/TC ratio, whereas dl-propargylglycine (PPG) (a H(2)S-generating enzyme cystathionine gamma lyase inhibitor) exacerbated lipid accumulation and augmented TC and EC concentrations and EC/TC ratio. Incubation of 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI)-oxLDL led to lipoprotein binding and uptake of macrophages, which was blunted by NaHS, but enhanced by PPG. Furthermore, OxLDL markedly induced CD36, scavenger receptor A (SR-A) and acyl-coenzyme A:cholesterol acyltransferase-1 (ACAT-1) expressions in macrophages, which was suppressed by NaHS (50-200 µmol/L). Finally, the down-regulations of TC and EC concentrations as well as CD36 and ACAT-1 expressions by NaHS were suppressed by glibenclamide, a K(ATP) channel blocker, but facilitated by PD98059, an extracellular signal-regulated kinases 1 and 2 (ERK1/2) inhibitor. These results suggested that H(2)S inhibits foam cell formation by down-regulating CD36, SR-A and ACAT1 expressions via the K(ATP)/ERK1/2 pathway in human monocyte-derived macrophages.

[Diagnosis and treatment of sacrococcygeal teratoma in adults: analysis of 17 cases].

OBJECTIVE: To investigate the diagnosis and treatment of sacrococcygeal teratoma in adults. METHODS: The clinical data of 17 patients with sacrococcygeal teratoma confirmed by pathological examination, 9 males and 8 females, aged 20 - 53, were analyzed retrospectively. RESULT: Correct diagnosis was made pre-operatively in 13 of the 17 patients. Two cases were misdiagnosed as with leiomyoma, and 2 cases as with sacrococcygeal cyst. Pathological examination confirmed the diagnosis of teratoma in all 17 cases. Thirteen patients were followed up for 1 - 5 years post-operatively. Malignant change was seen in 1 case, and 1 patient died 1 year after operation. Two patients suffered a relapse and then fully recovered after re-operation, and the other 15 patients all recovered without relapse. CONCLUSION: Sacrococcygeal teratoma in adults usually has no typical clinical symptom and signs and is often misdiagnosed. The pathologic examination is the base to make a definite diagnosis. Complete excision is necessary to prevent local recurrence and potential malignant transformation. The sacrococcygeal approach or combined abdominal-sacral approach is recommended.

Dynamic changes and clinical significance of serum Thl/Th2 cytokines in hemorrhagic fever with renal syndrome / 中国地方病学杂志

Objective To investigate the changes and pathogenic significance of serum interleukin-12p70 (IL-12), intefferon-γ,(IFN-γ) and IL-4 in the course of hemorrhagic fever with renal syndrome(HFRS). Methods Twenty five eases were divided into mild group (14 eases) and severe group (11 cases) according to the severity of illness. Blood samples were collected in various stages(fever, hypotensian and oliguria,diuresis stage). Serum IL-12 and IFN-γ levels were determined by enzyme-linked immunoserbent assay(ELISA), IL-4 by radioimmunoassay (RIA), blood urea nitrogen (BUN) and platelet by automatic biochemical analyzer and blood analyzer. Results Serum IL-12 levels in mild and severe groups were significantly different during various stages of HFRS (F=5.765, P<0.01). The IL-12 level of both patient groups significantly increased(P<0.01) in fever[ (0.87±0.38), (1.08± 0.77)μg/L], hypotension and oliguria [ (0.77±0.21), (2.11±2.13)μg/L] ,and diuresis stage [ (1.42±1.10), (1.20±0.88)μg/L], compared with control group [(0.56±0.10)μg/L]. In various stages, IFN-γ levels of both case groups were respectively (8.04±13.05), (5.94±8.24), (15.95±18.05), (4.41±4.10), (1.09±1.24), (1.38±1.74), (1.12±1.26), (0.19±1.29)μg/L, and the difference was statistically significant compared with control [ (0.27±0.15)rig/L]. K,-4 levels did not change significantly in the stages(F=0.682, P0.05), while the ratios of IFN-γ and IL-4 contents in mild and severe cases were significantly higher than control [(0.36±0.26) μg/L] in fever[ (2.46±3.52), (16.92±22.77)p.g/L], hypotension and oliguria[(2.52±2.72), (1.77±2.06) μg/L],diuresis stage [(1.45±2.28), (2.32±3.98)μg/L], the difference had statically significant (P<0.05 or 0.01).The curve of IL-12 was similar to that of BUN, but was contrary to blood platelet count. Conclusions The elevated levels of IL-12 and IFN-γ, with the imbalance of Th1/Th2 might be the main cause of systemic inflammatoryresponse and involved in the pathogenesis of HFRS.

Clinical and molecular analysis of hereditary non-polyposis colorectal cancer in Chinese colorectal cancer patients.

AIM: To analyze the frequency of hereditary non-polyposis colorectal cancer (HNPCC) in Chinese colorectal cancer (CRC) patients, and to discuss the value of microsatellite instability (MSI) and/or immunohistochemistry (IHC) for MSH2/MLH1 protein analysis as pre-screening tests in China. METHODS: The Amsterdam criteria I and II (clinical diagnosis) and/or germline hMLH1/hMSH2 mutations (genetic diagnosis) were used to classify HNPCC families. Genetic tests, including microsatellite instability, immunohistochemistry for MSH2/MLH1 proteins and hMSH2/hMLH1 genes, were performed in each proband. RESULTS: From July 2000 to June 2004, 1988 patients with colorectal cancer were analysed and 114 CRC patients (5.7%) from 48 families were categorized as having HNPCC, including 76 from 26 families diagnosed clinically and 38 from the other 22 families diagnosed genetically. The sensitivity and specificity of high MSI and IHC for predicting mutations were 100% and 54%, and 79% and 77%, respectively. CONCLUSION: The frequency of HNPCC is approximately 10% among all Chinese CRC cases. The MSI and IHC detections for hMSH2/hMLH1 proteins are reliable pre-screening tests for hMLH1/hMSH2 germline mutations in families suspected of having HNPCC.