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BACKGROUND The pandemic of the coronavirus disease 2019 (COVID-19) resulted in an increased prevalence of social isolation and loneliness in recent years. Although there is increasing evidence of an association between social isolation/loneliness and mortality in general, the role of social isolation and loneliness in the risk of single and multiple cardiometabolic diseases (CMD) remains controversial or even unknown. OBJECTIVE Here we aimed to determine whether social isolation and loneliness are associated with risk of CMD and cardiometabolic multimorbidity (CMM). METHODS 343,425 individuals with no CMD at baseline (stage I) and 35,209 individuals with only one CMD at baseline (stage II) were included. The exposures were self-reported isolation (including three levels, based on living alone, few contact with family or friends, and disengagement in group activities) and loneliness (including three levels, based on feeling lonely and able to confide). The main outcomes were CMD and CMM which was defined as the coexistence of at least two CMDs: diabetes mellitus (DM), coronary heart disease (CHD), and stroke. Cox proportional hazards models were performed to estimate hazard ratios (HRs) and their 95% CIs. RESULTS Both in stage I and stage II, social isolation and loneliness were associated with the incidence of CMD and CMM. In the multivariable adjusted models, compared with the least isolated, the most isolated had higher risks of incident CMD (HR 1.07, 95% CI 1.03 to 1.11) and CMM (HR 1.24, 95% CI 1.12 to 1.36) in stage I, and higher risk of incident CMM in stage II (HR 1.14, 95% CI 1.05 to 1.23). Compared with the least loneliness, those who were most loneliness had about 20% increased risk of CMD and 29% increased risk of CMM in stage I. The most loneliness was also significantly associated with increased CMM risk (HR 1.30, 95% CI 1.19 to 1.42) in stage II. Results of stratified analysis showed that living alone and feeling lonely, in particularly the latter, were much more strongly associated with higher risk of single CMD and CMM. Interestingly, social isolation has little direct effect on the risk of developing CHD, less social contact, as one of the high-risk social isolation factors, indeed increases the risk of incident CHD (HR, 1.05; 95% CI, 1.00-1.11).Moreover,poor diet strengthened the unfavorable association with cardiometabolic outcomes among the most isolated and the loneliest. CONCLUSIONS This study revealed the different risk associations of social isolation and loneliness with individual CMD and CMM. Identifying high-risk populations through the level of social participation and loneliness could help to prevent CMD and CMM. Health policies improving the state of living alone, less social contact and feeling lonely might be applicable for the precise prevention and treatment of these conditions. Moreover, ideal healthy diet promotion might substantially attenuate the risks for CMM and CMD among the isolated and lonely people.

Profilin-1 is involved in macroangiopathy induced by advanced glycation end products via vascular remodeling and inflammation

The combination of polymers with ionic liquids (ILs) is of significant interest for a variety of possible applications e.g., polymer electrolytes, nanoencapsulations and actuators. Knowledge of phase separation, crystallization and their interplay in polymer/IL mixtures is of crucial importance for realizing these applications. In this work, the effect of phase separation on crystallization behavior for poly(ethylene oxide)/1-ethyl-3-methylimidazolium tetrofluoroborate (PEO/[EMIM][BF4]) mixtures with a lower critical solution temperature (LCST) was investigated for the first time. It is demonstrated that the crystallization of PEO/ILs mixtures could be highly accelerated by phase separation as the blended samples are quenched from two-phase region compared to those quenched from homogenous state. This phenomenon can be on one hand ascribed to the disruption of hydrogen bonds between PEO and IL molecules as evidenced by FTIR results, which causes an increase of chain mobility and diffusivity for developing a spherulite embryo, and on the other hand due to fluctuation concentration where local PEO-rich domains with higher crystallizable PEO concentration will exist, even though the interfacial area has disappeared upon quenching to the crystallization. The facilitating effect of phase separation on crystallization becomes more prominent as driven by spinodal decomposition (50 wt% PEO) than that driven by nucleation & growth (70 wt% PEO). This work will provide a new possibility to optimize the performance of polymer electrolytes by regulating the phase morphologies of polymer/IL blends.

A HVDC grid based on voltage source converter (VSC) is an attractive solution for the grid integration of offshore renewable energy, interconnection of ac grids, facilitation of power markets, and energy emergency support. However, the power flow within the dc grids is determined by the line resistance and cannot be fully controlled by the VSCs only. Thus, power flow control of dc grids are needed not only to realize the economic operation and power markets, but also to prevent overload of dc lines in post-fault conditions. Four types of control devices, dc transformer, the variable resistor, series voltage source and interline dc power flow controller (IDCPFC) are presented to achieve the goal of power flow controlling. This paper presents a dc power flow controller (DCPFC) based on dc converter. This DCPFC can be extended to multi-terminal power flow control in dc power grids. The operation principle of the proposed DCPFC is analyzed. And the theoretical analysis is validated by a full-scaled simulation.

This paper introduces the modular multilevel converter(MMC), analyzes five modulation strategies of the multilevel structures: carrier phase shift pules width modulation(CPS-PWM), carrier overlap modulation, carrier rotation modulation, nearest level modulation(NLM) and incremental capacitance equalization algorithm with voltage upper and lower limits. In order to analysis the dynamic performance, including harmonic component, switching loss, and characteristics of capacitor ripples of MMC, the simulation experiments were completed in PLECS. After comparison, it is found that there are different results when measuring the merits of modulation strategies from different standards. On this basis, this paper presents the optimal modulation strategies in different scenarios, and also provides a direction for future improvement.

Background Atherosclerosis is a chronic inflammatory disease. Accumulating evidence suggests that long non-coding RNAs (lncRNAs) and microRNAs have emerged as critical regulators of atherosclerosis; however, whether they have crosstalk on this issue remains elusive. Here, we investigated the potential associations between lncRNA-MALAT1 and miR-155 on the regulation of atherosclerosis. Methods Quantitative real-time PCR was employed to assess the expression of MALAT1, IL-6 and IL-8. ELISA was performed to measure the secretion of IL-6 and IL-8. MTT assay was used to determine the proliferation of Human Coronary Artery Endothelial Cells (HCAECs). Flow cytometry was used to measure the cell apoptosis. Western blot was used to assess the expression of apoptosis-related proteins and the phosphorylation of STAT1 and STAT3. Results We found that the pro-inflammatory cytokine release and the apoptosis of HCAECs were elevated upon ox-LDL treatment, while MALAT1 expression was also up regulated. Knocking down of MALAT1 boosted ox-LDL-induced cytokine release and apoptosis of HCAECs. The binding site of miR-155 in MALAT1 sequence was confirmed by dual luciferase assay. Furthermore, miR-155 inhibition significantly repressed ox-LDL mediated inflammation and apoptosis of HCAECs via SOCS1. At last, we found that MALAT1 could suppress the inflammatory cytokine release and cell apoptosis via sponging miR-155 to increase SOCS1 level, which in turn restrained JAK-STAT pathway. Conclusion In summary, this study revealed the mechanisms by which MALAT1 worked as a putative atherosclerosis suppressor via miR-155 and SOCS1. Therefore, modulation of MALAT1/miR-155/SOCS1 axis might alleviate the inflammation persisted in atherosclerosis.

Extracellular adenosine diphosphate (ADP) mediates a wide range of physiological effects as an extracellular signaling molecule, including platelet aggregation, vascular tone, cell proliferation, and apoptosis by interacting with plasma membrane P2 receptors. However, the effect of ADP on cell proliferation was contradictory. In this study, we found that ADP significantly inhibited cell proliferation of human umbilical vein endothelial cells at high concentrations (50 to 100 µM). Treatment with ADP did not induce cell apoptosis but instead induced cell cycle arrest in the S phase, which may be partly due to the downregulation of cyclin B1. The inhibition of cell proliferation was blocked by suramin, a nonspecific antagonist of the P2 receptors, and high concentrations of ADP significantly upregulated the messenger RNA (mRNA) and protein expression of P2Y11 in endothelial cells. Moreover, the downregulation of P2Y11 by RNA interference reversed the inhibition of cell proliferation. In addition, ADP (100 µM) can induce the formation of cytosolic autophagy in endothelial cells and a rapid phosphorylation of extracellular signal regulated kinase (ERK) 1/2, which is a canonical signal molecule downstream of P2Y receptors, accompanied by a mRNA expression of proinflammatory cytokines such as intercellular adhesion molecule 1 and vascular cell adhesion molecule 1. Taken together, our study excludes a mechanism for extracellular ADP impairing endothelial cells proliferation via P2Y11 receptor by downregulating cyclin B1 and arresting cell cycle at the S phase, besides, ADP induces cell autophagy and mRNA expression of inflammatory cytokines, whether it is mediated by Erk signaling pathways needs further studies to confirm.

Phase separation kinetics of dynamically asymmetric mixtures poly(ethylene oxide)/ionic liquid (PEO/[EMIM][BF4]) was investigated through optical microscopy and rheological measurements. The distinct phase-separating morphologies including network structure at lower PEO concentrations of 10∼30 wt % (P10, P30) driven by viscoelastic phase separation (VPS), co-continuous structure at the moderate concentrations (P40, P50) governed by spinodal decomposition (SD) and droplets-matrix at higher concentrations (P60, P70) driven by either SD or nucleation and growth (NG) are observed under different temperatures. Evident deviation of the storage modulus G′ and gel-like behavior on loss tangent tanδ at low frequencies can be seen upon entering into the two-phase region dependent on different morphologies. During time sweeps, the initial increase of G′ can be ascribed to the growth of concentration fluctuation, and the subsequent decrease possibly due to the phase domain coarsening, breaking up or coalescence. The interfacial tension σ at the late stage of phase separation with droplet-matrix morphologies is estimated by using the Gramespacher-Meissner (G-M) model and Palierne model.

Activation of TLR4-MyD88-NF-κB signaling by lipopolysaccharide (LPS) evokes a proinflammatory immune response, and plays a pivotal role in initiation and progression of atherosclerosis (AS). ATP (adenosine 5'-trisphosphate), a powerful extracellular signal transduction molecule, functions to regulate immune inflammatory responses depending on the type of P2 receptors and cell lines. In this study, we first performed RT-PCR to detect the mRNA expression of monocyte chemoattractant protein-1 (MCP-1), IL-8, and IL-1β induced by different concentrations of LPS in human umbilical vein endothelial cells (HUVECs). Protein level of TLR4 signaling including TLR4, myeloid differentiation factor (MyD88), and CD14 induced by LPS (1 μg/mL) at different times (0, 10, 30, 60, 120 min) was analyzed by Western blot. Then, RT-PCR was performed to detect the effect of different concentrations of ATP on mRNA expression of IL-1β and MCP-1 induced by LPS (1 μg/mL) and the TLR4 signaling pathway. Western blot was performed to detect the effect of low concentrations of ATP on phosphorylation of p65 induced by 1 μg/mL LPS. Finally, we used P2Y receptor blocker Suramin to verify whether the role of ATP on LPS-induced inflammatory cytokine expression was through P2Y receptors. The results showed that LPS upregulated the expression of MCP-1, IL-8, and IL-1β in a dose-dependent manner accompanied by the activation of TLR4-MyD88 signaling in HUVECs. Only low concentration ATP (1, 10 μM) inhibited LPS-induced mRNA expression of IL-1β and MCP-1. ATP at low concentrations also downregulated the mRNA expression of TLR4, CD14, and MyD88 and inhibited LPS-induced phosphorylation of p65. Furthermore, Suramin, a nonspecific P2Y receptor antagonist, did not attenuate the inhibition of ATP on LPS-induced IL-1β and MCP-1 expression. Taking this together, low concentration ATP inhibited LPS-induced inflammation in HUVECs by negatively regulating TLR4-MyD88 signaling, and P2Y receptors were not involved in this process, which might provide new ideas for prevention and treatment of inflammatory diseases such as AS.

RNA‐binding properties of nucleolin play a fundamental role in regulating cell growth and proliferation. We have previously shown that nucleolin plays an important regulatory role in the phenotypic transformation of vascular smooth muscle cells (VSMCs) induced by angiotensin II (Ang II). In the present study, we aimed to investigate the molecular mechanism of nucleolin‐mediated phenotypic transformation of VSMCs induced by Ang II. Epidermal growth factor (EGF) and platelet‐derived growth factor (PDGF) inhibitors were used to observe the effect of Ang II on phenotypic transformation of VSMCs. The regulatory role of nucleolin in the phenotypic transformation of VSMCs was identified by nucleolin gene mutation, gene overexpression and RNA interference technology. Moreover, we elucidated the molecular mechanism underlying the regulatory effect of nucleolin on phenotypic transformation of VSMCs. EGF and PDGF‐BB played an important role in the phenotypic transformation of VSMCs induced by Ang II. Nucleolin exerted a positive regulatory effect on the expression and secretion of EGF and PDGF‐BB. In addition, nucleolin could bind to the 5′ untranslated region (UTR) of EGF and PDGF‐BB mRNA, and such binding up‐regulated the stability and expression of EGF and PDGF‐BB mRNA, promoting Ang II‐induced phenotypic transformation of VSMCs.

Objective To observe the effect of selectively inhibiting STAT3 on the production of IL-8 and cell apoptosis of THP-1 cells by Stattic, and explore the underlying mechanism. Methods THP-1 cells were treated with different concentrations of Stattic ( 0, 1, 5, 10, 15, 20 μmol/L) for 0, 1, 3, 6, 12, 24 hours. Reverse transcription PCR or real-time PCR was performed to detect the mRNA expression of IL-8, IL-6, IL-1β and tumor necrosis factor-α (TNF-α); ELISA was used to detect the protein expression of IL-8; flow cytometry was applied to evaluate the apoptosis of THP-1 cells; and Western blot analysis was performed to detect the phosphorylation of STAT3 and extracellular signal-regulated kinase (ERK). Reverse transcription PCR was used to test the effect of U0126 at different concentrations (0, 1, 5, 10 μmol/L) on the mRNA expression of IL-8 induced by Stattic in THP-1 cells. Results Stattic significantly up-regulated the mRNA and protein expression of IL-8 in THP-1 cells in a concentration range of 10~20 μmol/L, and induced cell apoptosis only at high concentration (15, 20 μmol/L). Treated with Stattic for 0, 1, 3, 6, 12, 24 hours, IL-8 mRNA was significantly up-regulated, and after 6 hours, the expression of IL-8 protein and apoptosis of THP-1 cells were up-regulated in a time-dependent manner. STAT3 phosphorylation was inhibited in a time- and dose-dependent manner by Stattic. ERK phosphorylation was induced by different concentrations of Stattic in a time-dependent manner. In addition, U0126, a selective inhibitor of ERK pathway, inhibited Stattic-induced IL-8 expression in a concentration-dependent manner. Conclusion Stattic, a selective STAT3 inhibitor, can induce the apoptosis and IL-8 production by activating ERK signaling pathway in THP-1 cells.

To investigate the effects of adenosine triphosphate (ATP) on expression of inflammatory factors induced by lipopolysaccharide (LPS) in endothelial progenitor cells (EPCs), and to elucidate the possible mechanisms. Methods: Mononuclear cells were isolated from human umbilical cord blood by density gradient centrifugation, RT-PCR was performed to detect the expression of inflammatory factors induced by LPS (1 mg/mL) in EPCs, the effect of low concentration (5 μmol/L) of ATP on expression of IL-1β, MCP-1 and ICAM-1, and the effect of different concentrations (5, 50 μmol/L) of ATP on the expression of Toll-like receptor (TLR) 4, myeloid differentiation primary response protein 88 (MyD88) and CD14. Western blot was performed to detect expression of TLR4 regulated proteins MyD88 and CD14 or to detect the low concentration (1, 5 μmol/L) of ATP on the expression of TLR4, MyD88 and CD14 and the NF-κB signaling pathway. Results: EPCs highly expressed TLR4, and its ligand LPS (1 mg/mL) significantly upregulated mRNA expression of IL-1β, MCP-1 and ICAM-1 and protein expression of MyD88 and CD14 in a time-dependent manner (P0.01), accompanied by activation of ERK and NF-κB signal pathway. ATP at low concentration (5 μmol/L) significantly inhibited LPS-induced mRNA expression of IL-1β, MCP-1 and ICAM-1(P0.05), downregulated the LPS-induced protein expression of TLR4, MyD88 and CD14 in EPCs (P0.05), and suppressed LPS-induced activation of NF-κB signaling pathway (P0.05). Conclusion: ATP at low concentration may suppress LPS-induced expression of inflammatory factors in EPCs through negative regulation of the TLR4 signaling pathway.目的：分析三磷酸腺苷(adenosine triphosphate，ATP)对脂多糖(lipopolysaccharide，LPS)诱导内皮祖细胞(endothelial progenitor cells，EPCs)表达炎症细胞因子的影响，并探讨其机制。方法：采用密度梯度离心法分离人脐血单个核细胞，用RT-PCR检测LPS(1 mg/mL)诱导EPCs表达炎症细胞因子的情况，低浓度的ATP(5 μmol/L)对LPS诱导EPCs表达细胞炎症因子的影响，不同浓度(5，50 μmol/L)的ATP对EPCs中TLR4，MyD88和CD14 mRNA表达的影响；Western印迹检测LPS(1 mg/mL)对EPCs表达TLR4调节蛋白MyD88和CD14的影响以及信号通路的活化情况，低浓度ATP(1，5 μmol/L)对LPS诱导EPCs表达TLR4，MyD88和CD14的影响以及信号通路的活化情况。结果：EPCs高表达TLR4，其配体LPS(1 mg/mL)显著上调IL-1β，MCP-1和ICAM-1的mRNA表达(均P0.01)，并呈时间依赖性上调MyD88和CD14蛋白的表达，同时活化ERK和NF-κB信号通路。低浓度ATP抑制LPS诱导的IL-1β，MCP-1和ICAM-1 mRNA的表达(均P0.05)，同时也下调LPS诱导的TLR4，MyD88和CD14蛋白的表达(P0.01或P0.05)，并抑制LPS诱导的NF-κB信号通路的活化(P0.05)。结论：ATP在低浓度时通过负性调节TLR4信号通路而抑制LPS诱导的炎症细胞因子在EPCs中的表达。.

The phase separation behavior of poly(ethylene oxide) (PEO) in ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF4]) was investigated by rheological, optical microscopy, FT-IR and DSC measurements. It is demonstrated that specific interactions, particularly the hydrogen bonding between PEO and the ionic liquids as evidenced by FT-IR, in which a subtle but apparent absorption peak shift near the phase transition appears, account for the unusual low critical solution temperature (LCST) phase separation. Unlike the typical trend in which the storage modulus G′ simply increases with temperature near the phase boundary for polymer blends without specific interaction, in our study, a novel “V-shaped” rheological response is observed, namely a dip in G′ followed by an upturn, especially at low PEO concentration (

Nucleotide-binding oligomerization domain containing 2 (NOD2)-induced signal transduction and cytokine production is regulated by a number of factors. However, the feedback effect of the pro-inflammatory TNF-α on NOD2-induced inflammation is not fully understood. In this study, we found unexpectedly that TNF-α up-regulated NOD2 ligand MDP-induced production of the CXC chemokines, including CXCL1, 2, and 8, and the pro-inflammatory cytokines, including IL-1β, IL-6, and TNF-α, in a dose-dependent manner at both mRNA and protein levels in monocytic THP-1 cells. Though TNF-α induced the up-regulation of ubiquitin-editing enzyme A20, an important negative regulator for Toll-like receptor- and NOD2-induced inflammatory responses, the over-expression of A20 by gene transfer did not reversed MDP-induced production of cytokines, suggested that A20 did not regulate the functions of NOD2 in THP-1 cells. Meanwhile, we found that TNF-α up-regulated NOD2 and its down-stream adaptor protein RIP2 at both mRNA and protein levels. MDP induced the activation of ERK, JNK, p38 and NF-κB, and TNF-α pre-treatment augmented this activation. The results from pharmacological inhibition assay showed that cytokine production was dependent on MAPK signaling. In addition, we found that the pre-treatment of THP-1 cells with MDP down-regulated the mRNA levels of cytokine induced by MDP re-treatment. MDP pre-treatment up-regulated NOD2, but down-regulated RIP2, and down-regulated NOD2 signal transduction induced by MDP re-stimulation. Taking together, these results suggested that TNF-α is a positive regulator for NOD2 functions via up-regulation of NOD2 and its signal adaptor RIP2, and TNF-α-induced A20 does not regulate MDP-induced inflammatory responses in THP-1 cells. J. Cell. Biochem. 119: 5072-5081, 2018. © 2017 Wiley Periodicals, Inc.

To explore Toll-like receptor 2 (TLR2) and TLR4 polymorphism in Han people from Hunan region and its association with coronary atherosclerotic heart disease. Methods: Sanger sequence and statistical analysis were performed to identify the polymorphism of TLR2 and TLR4 genes in 347 unrelated Hunan Han subjects, including 180 healthy people (control group) and 167 patients with coronary atherosclerotic heart disease (coronary atherosclerotic heart disease group). Results: There was no significant difference in the genotype frequency and allelic frequency for TLR2 SNP2258GA and TLR4 SNP896AG between the 2 groups (P0.05), while there was significant difference in the TLR4 SNP1196CT between the 2 groups (P0.05). Conclusion: TLR4 SNP1196CT polymorphism is associated with coronary atherosclerotic heart disease in Chinese Han populationin in Hunan region.目的：探讨湖南地区汉族人群Toll样受体(Toll-like receptor 2，TLR2)及TLR4基因多态性与冠状动脉粥样硬化性心脏病(冠心病)的关系。方法：运用Sanger测序技术检测180例正常对照组及167例无血缘关系湖南汉族人群冠心病组中TLR2 SNP 2258AG及TLR4 SNP896AG和SNP1196CT的多态性。结果：TLR2 SNP 2258AG及TLR4 SNP896AG基因型频率和等位基因频率在冠心病组和正常对照组之间的分布差异无统计学意义(P0.05)，TLR4 SNP1196CT在两者之间差异有统计学意义(P0.05)。结论：湖南地区汉族人群TLR4基因多态性位点SNP1196CT与冠心病有关。.

Morphology and crystallization behavior of poly(ɛ-caprolactone) (PCL) in its 80/20 blends with poly(styrene-co-acrylonitrile) (SAN) containing hydrophobic or hydrophilic nanosilica was investigated. It was found that hydrophilic nanosilica displayed a more significant refinement effect on co-continuous morphology of PCL/SAN blends than hydrophobic nanosilica for its selective distribution within the PCL matrix but closer to the two-phase interface. Ring-banded spherulites were observed in both kinds of nanosilica-filled blends, the periodic distance of which decreased with increasing nanosilica content. Hydrophilic nanosilica reduced the dependence of the periodic distance of ring-banded spherulites on the crystallization temperature more efficiently than hydrophobic nanosilica. Furthermore, crystallization process of PCL/SAN blends filled with hydrophobic nanosilica was suppressed as the restriction effect of nanosilica on the crystal growth always outweighed their heterogeneous nucleation effect. In contrast, low content of hydrophilic nanosilica (≤1 wt %) were more likely to exhibit growth restriction effect rather than nucleation effect, whereas heterogeneous nucleation effect of higher content of hydrophilic nanosilica (>1 wt %) dominated over growth restriction effect on facilitating the crystallization behavior. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44157.

Extracellular nucleotides mediate a wide range of physiological effects by interacting with plasma membrane P2 purinergic receptors. P2 receptors are expressed in certain kinds of stem cells, and function to induce cytokine expression and to modulate cell proliferation. We have analysed the expression and the function of P2 receptors in human umbilical cord blood-derived EPCs (endothelial progenitor cells). EPCs expressed P2X4,6,7 and P2Y2,4,11,13,14 receptors and extracellular ATP inhibited EPCs proliferation. As in a previous study, EPCs expressed functional TLR4 (Toll-like receptor 4) and activation of TLR4 by LPS (lipopolysaccharide) evoked a pro-inflammatory immune response. When human EPCs were stimulated with LPS and nucleotides, ATP or UTP inhibited the expression of pro-inflammatory cytokines including MCP-1 (monocyte chemoattractant protein-1), IFNα (interferon α), TNFα (tumour necrosis factor α) and adhesion molecule VCAM-1 (vascular cell adhesion molecule 1) induced by LPS. ATP and UTP also down-regulated the gene expression of TLR4, CD14 and MyD88 (myeloid differentiation factor 88), a TLR adaptor molecule, and protein expression of CD14 and MyD88. Moreover, the phosphorylation of NF-κB (nuclear factor κB) p65 induced by TLR4 activation was inhibited partly by ATP or UTP at concentrations of 1-5 μM. These results suggest that extracellular nucleotides negatively regulate EPCs proliferation and TLR4 signalling.

Muramyldipeptide (MDP), the minimum essential structure responsible for the immuno-adjuvant activity of peptidoglycan, is recognized by intracellular nuclear-binding oligomerization domain 2 (NOD2). Here, we obtained evidence that the treatment of human aortic endothelial cells (HAECs) with MDP up-regulated the gene expression of type I interferons in a dose- and time-dependent manner. MDP also up-regulated the expression of the receptor NOD2, suggesting that MDP may induce a positive feedback response. The up-regulation of interferons was not dependent on the TNFa signaling, as HAECs did not express TNFa with the stimulation of MDP, and TNFa neutralizing antibody did not decrease the induction of IFNs induced by MDP. RT-PCR results showed that HAECs expressed the gene transcripts of interferon regulatory factor (IRF) 1, 2, 3, 9. The western blot results showed that MDP induced the phosphorylation of IRF3. These results suggested that MDP induced the up-regulation of gene transcript of interferons through the activation of IRF3 signaling pathway. Meanwhile, MDP induced the gene expression of pro-inflammatory cytokines, including IL-1s, IL-8, and MCP-1. Taken together, these results suggested that HAECs may play roles in the anti-infection immune response and in the induction of innate immunity.

Previous studies have demonstrated that endothelial progenitor cells (EPCs) could delay the progress of vascular remodeling in blood vessel-proliferating diseases. The proliferation of vascular smooth muscle cells (VSMCs) is a pivotal factor in cardiovascular diseases. In this study, we investigated whether EPCs could inhibit the Angiotensin II (Ang II)-induced proliferation of VSMCs. The effect of early EPC-conditioned medium (E-EPC-CM), late EPCs-CM (L-EPC-CM), and HUVEC-CM on Ang II-induced proliferation of VSMCs was assessed by BrdU incorporation, total protein content, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays, and flow cytometry. Reverse transcriptase-polymerase chain reaction and Western blot were performed to analyze the effect of different CMs on Ang II-induced phosphorylations of ERK, JNK, p38, and NF-κB subunit p65 and the expressions of c-myc and c-fos. E-EPC-CM, L-EPC-CM, and HUVEC-CM significantly inhibited the Ang II-induced DNA synthesis, total protein expression, cell survival, and cell cycle progress of VSMCs. Furthermore, E-EPC-CM significantly inhibited the Ang II-induced phosphorylation of ERK, JNK, p38, and p65 (nuclear translocation of p65) and the expressions of c-myc and c-fos. Taken together, these data suggested that EPCs may delay the progress of vascular remodeling in blood vessel-proliferating diseases by inhibiting Ang II-induced proliferation of VSMCs through inactivating MAPKs and NF-κB signaling pathways and by reducing the expressions of c-myc and c-fos.

Toll-like receptor 3 (TLR3), a member of the TLR family that recognizes double-stranded RNA (dsRNA), plays an important role in antiviral immunity. TLR3 is widely expressed in various cells and the activation of TLR3 induces cell apoptosis in some cells. However, the effect of TLR3 on cell proliferation in endothelial progenitor cells (EPCs) is unclear. In this study, we found that EPCs expressed high levels of TLR1, 3, 4, and 6 and low levels of TLR2, 5, 7, 8, and 10. The treatment of EPCs with TLR3 agonist Poly I:C up-regulated the expression of cytokines IL-1β, IL-6, IL-8, TNF-α, IFN-α, and IFN-β, indicating that EPCs expressed functional TLR3. Moreover, Poly I:C treatment induced cell cycle progress inhibition and cell apoptosis, leading to the inhibition of cell proliferation. Further studies indicated that IL-1β was involved in TLR3-induced cell proliferation inhibition, as IL-1β inhibited cell proliferation in a dose-dependent manner, and the IL-1β receptor type I (IL-1R1)-neutralizing antibody ameliorated Poly I:C-induced cell proliferation inhibition. Taken together, these results suggest that Poly I:C impairs cell proliferation by inducing cell cycle progress inhibition and cell apoptosis via TLR3 in EPCs.

We have recently demonstrated that endothelial progenitor cells (EPCs) inhibit AngII-induced proliferation of vascular smooth muscle cells (VSMCs) by inactivating MAPKs and NF-κB signaling pathway and reducing expression of oncogene c-myc and c-fos. The inhibitory effect of EPCs on VSMCs is associated with paracrine mechanism. However, the potential mechanism of EPCs on the regulation of AngII-induced proliferation of VSMCs was unknown. Calcitonin gene-related peptide (CGRP) could inhibit AngII-induced proliferation and transformation of VSMCs. However, it has not been known whether CGRP released from EPCs is a potential regulator in regulation of AngII-induced proliferation of VSMCs. Early endothelial progenitor cell-conditioned medium(E-EPC-CM) was pre-incubated with functional blocking antibodies against CGRP for 1 h or VSMCs was preteated with CGRP(837)(CGRP receptor antagonist) for 1 h before VSMCs were pretreated with CM for 30 min. DNA synthesis ability, total protein levels, cell survival, signal transduction, and expressions of c-myc and c-fos of VSMCs induced by AngII (10(-6)mol/l) were detected to assess the role of CGRP in AngII-induced proliferation of VSMCs. E-EPC-CM could significantly inhibit AngII-induced DNA synthesis ability, total protein levels, cell survival, phosphorylation of ERK, JNK, p38, p65, and expressions of c-myc and c-fos compared with the control group(P < 0.05). However, Pretreatment with anti-CGRP antibody and CGRP(837) could significantly weaken the inhibitory effect of E-EPC-CM on proliferation of VSMCs induced by AngII (P < 0.05). EPCs exert anti-proliferative effects on VSMCs mediated by the release of CGRP.

Endothelial dysfunction is involved in various cardiovascular diseases such as atherosclerosis. Endothelial progenitor cells (EPCs) contribute to re-endothelialization and neo-vascularization, and the increase of EPCs in peripherial circulation benefits the prognosis of cardiovascular disease. However, little is known about the biological stimuli that initiate the proliferation and the maintenance of stem cell phenotype of EPCs. Here we reported that human umbilical vein blood derived EPCs expressed gene transcripts coding for Toll-like receptor (TLR) 1-6, TLR8-10, TLR4 co-receptor CD14, and myeloid differentiation factor 88 (MyD88), a TLR adaptor molecule. Protein expression of TLR2, 4, CD14, and MyD88 was also detected by FACS or Western blot. The activation of TLR4 by LPS modulated the expression of TLRs, induced the phosphorylation of NF-kappaB, P38, and ERK42/44, and up-regulated the gene expression of cytokines IL-8, IFN-alpha, IFN-beta, and TNF-alpha, suggesting EPCs expressed functional TLR4. Unexpectedly LPS treatment failed to induce apoptosis in EPCs, but instead promoted cell proliferation of EPCs. Furthermore, the treatment of EPCs with LPS up-regulated stem cell markers AC133 and CD34 in both mRNA and protein levels, and down-regulated the protein expression of differential marker eNOS. These results suggested that TLR4 functions to maintain the stem cell phenotype of EPCs and enlarge its population, which reveals a novel aspect of the multiple-faced TLR biology, and may open new prospects for using TLR4 agonists to promote the production of EPCs for clinical use.

The irreversible and reversible phase transition behaviors during phase separation-recovery (heating–cooling) cycles for poly(ethylene oxide)/1-ethyl-3-methylimidazolium tetrafluoroborate ionic liquid (PEO/[EMIM][BF4]) mixtures with a lower critical solution temperature phase diagram are reported for the first time. The evident differential scanning calorimetry endothermic and exothermic peaks are observed during the heating–cooling scan cycles near the phase boundary, in which the large heat loss for samples below the critical composition (60 wt% PEO) and obvious downward shift of phase transition temperature for all the compositions between the first and second cycles are particularly attractive. After the first recovery process, a reversible behavior during the next cycles is expected. These interesting phenomena are further confirmed by optical microscopy and Fourier-transform infrared measurements. It is demonstrated that the disruption and partial recovery of the hydrogen bonds, combined with the conformational change of PEO chains, can contribute to this irreversible behavior as well as a conversion to reversible phase transition behavior.

Extracellular ATP mediates a wide range of physiological effects, including cell proliferation, differentiation, maturation, and migration. However, the effect of ATP on cell proliferation has been contradictory, and the mechanism is not fully understood. In the current study, we found that extracellular ATP significantly inhibited the proliferation of human umbilical vein endothelial cells (HUVECs) and human aortic endothelial cells (HAECs). Treatment with ATP did not induce cell apoptosis but instead induced cell cycle arrest in S phase. ATP induced the phosphorylation of ERK1/2, but the ERK inhibitors, U0126 and PD9809, did not regulate the inhibition of cell proliferation induced by ATP. However, ATP-induced inhibition of cell proliferation was blocked by suramin, a nonspecific antagonist of the P2Y receptors, and endothelial cells expressed P2Y11, a P2Y receptor that specifically binds ATP. Moreover, the down-regulation of P2Y11 by RNA interference not only reversed the inhibition of cell proliferation but also ameliorated cell cycle arrest in S phase. In addition, P2Y11 sensitized endothelial cells to cisplatin-induced cell death by down-regulation of the expression of Bcl-2. Taken together, these results suggest that extracellular ATP impairs cell proliferation by triggering signaling to induce cell cycle arrest and sensitizes cell to death via P2Y11 in endothelial cells.

To explore the effect of endothelial progenitor cells (EPCs) on the proliferation of co-cultured rat vascular smooth muscle cells (VSMCs).Mononuclear cells were isolated from fresh cord blood by 6% hydroxyethyl starch (HES) and density gradient centrifugation. Isolated mononuclear cells were cultured in EGM-2 medium supplemented with 20% fetal bovine serum (FBS), VEGF,bFGF and other growth factors. Biological features of EPCs were observed at different time points, and EPCs were identified by morphology, fluorescence double-staining and flow cytometry. Indirect immunofluorescence was performed to analyze the expression of alpha-SM-actin, calponin of VSMCs special antigen. Co-culture system of EPCs and VSMCs was established by transwell permeable support. FBS (20%) was used to stimulate the proliferation of VSMCs. In a VSMCs/EPCs co-culture system, the DNA synthesis ability, total protein level and cell cycle of VSMCs were determined by BrdU marking method,protein quantitation and flow cytometry after co-culture for 6, 12, 24,48 and 72 h.After co-culture for 12, 24, 48, and 72 h, the DNA synthesis ability and total protein level of VSMCs significantly decreased compared with the control group (P0.05). Flow cytometry showed that the percentage of S phase of VSMCs in VSMCs/EPCs co-cultured group significantly decreased and the percentage of G1 phase increased markedly compared with the control group (P0.05). The maximal inhibitory effect was observed at 48 h.Early EPCs could inhibit the proliferation of VSMCs.